Editorial: mark up algorithms about Events

Also fix a typo that Bikeshed was able to find thanks to this.

dom.bs

@@ -510,6 +510,7 @@ string.
 <p>The <dfn attribute for=Event><code>currentTarget</code></dfn> attribute must return the value it
 was initialized to. When an <a>event</a> is created the attribute must be initialized to null.
 
+<div algorithm>
 <p>The <dfn method for=Event><code>composedPath()</code></dfn> method steps are:
 
 <ol>
@@ -608,6 +609,7 @@ was initialized to. When an <a>event</a> is created the attribute must be initia
 
  <li><p>Return <var>composedPath</var>.
 </ol>
+</div>
 
 <p>The <dfn attribute for=Event><code>eventPhase</code></dfn> attribute must return the value it was
 initialized to, which must be one of the following:
@@ -703,6 +705,7 @@ initialized to.
 
 <hr>
 
+<div algorithm>
 <p>To <dfn export for=Event id=concept-event-initialize>initialize</dfn> an <var>event</var>, with
 <var>type</var>, <var>bubbles</var>, and <var>cancelable</var>, run these steps:
 
@@ -722,7 +725,9 @@ initialized to.
 
  <li><p>Set <var>event</var>'s {{Event/cancelable}} attribute to <var>cancelable</var>.
 </ol>
+</div>
 
+<div algorithm>
 <p>The
 <dfn method for=Event><code>initEvent(<var>type</var>, <var>bubbles</var>, <var>cancelable</var>)</code></dfn>
 method steps are:
@@ -733,6 +738,7 @@ method steps are:
  <li><p><a>Initialize</a> <a>this</a> with <var>type</var>, <var>bubbles</var>, and
  <var>cancelable</var>.
 </ol>
+</div>
 
 <p class=note>{{Event/initEvent()}} is redundant with <a>event</a> constructors and
 incapable of setting {{Event/composed}}. It has to be supported for legacy content.
@@ -792,6 +798,7 @@ dictionary CustomEventInit : EventInit {
 <p>The <dfn attribute for=CustomEvent><code>detail</code></dfn> attribute must return the value it
 was initialized to.
 
+<div algorithm>
 <p>The
 <dfn method for=CustomEvent><code>initCustomEvent(<var>type</var>, <var>bubbles</var>, <var>cancelable</var>, <var>detail</var>)</code></dfn>
 method steps are:
@@ -804,6 +811,7 @@ method steps are:
 
  <li><p>Set <a>this</a>'s {{CustomEvent/detail}} attribute to <var>detail</var>.
 </ol>
+</div>
 
 
 <h3 id=constructing-events>Constructing events</h3>
@@ -816,6 +824,7 @@ method steps are:
 <p class=note>This construct can be used by {{Event}} subclasses that have a more complex structure
 than a simple 1:1 mapping between their initializing dictionary members and IDL attributes.
 
+<div algorithm>
 <p>When a <dfn export for=Event id=concept-event-constructor>constructor</dfn> of the {{Event}}
 interface, or of an interface that inherits from the {{Event}} interface, is invoked, these steps
 must be run, given the arguments <var>type</var> and <var>eventInitDict</var>:
@@ -828,7 +837,9 @@ must be run, given the arguments <var>type</var> and <var>eventInitDict</var>:
 
  <li><p>Return <var>event</var>.
 </ol>
+</div>
 
+<div algorithm>
 <p>To
 <dfn export id=concept-event-create lt="creating an event|create an event">create an event</dfn>
 using <var>eventInterface</var>, which must be either {{Event}} or an interface that inherits from
@@ -858,13 +869,15 @@ it, and optionally given a <a>realm</a> <var>realm</var>, run these steps:</p>
 
  <li><p>Return <var>event</var>.
 </ol>
+</div>
 
 <p class=note><a>Create an event</a> is meant to be used by other specifications which need to
 separately <a lt="create an event">create</a> and <a>dispatch</a> events, instead of simply
 <a lt="fire an event">firing</a> them. It ensures the event's attributes are initialized to the
 correct defaults.</p>
 
-<p>The <dfn noexport>inner event creation steps</dfn>, given an <var>interface</var>,
+<div algorithm>
+<p>The <dfn noexport>inner event creation steps</dfn>, given an <var>eventInterface</var>,
 <var>realm</var>, <var>time</var>, and <var>dictionary</var>, are as follows:</p>
 
 <ol>
@@ -890,6 +903,7 @@ correct defaults.</p>
 
  <li><p>Return <var>event</var>.
 </ol>
+</div>
 
 
 <h3 id=defining-event-interfaces>Defining event interfaces</h3>
@@ -1246,6 +1260,7 @@ property of the event being dispatched.
 <p>Ideally, any new event APIs are defined such that they do not need this property. (Use
 <a href="https://github.com/whatwg/dom/issues">whatwg/dom</a> for discussion.)
 
+<div algorithm>
 <p>To <dfn export>legacy-obtain service worker fetch event listener callbacks</dfn> given a
 {{ServiceWorkerGlobalScope}} <var>global</var>, run these steps. They return a <a for=/>list</a> of
 {{EventListener}} objects.
@@ -1265,10 +1280,12 @@ property of the event being dispatched.
 
  <li><p>Return <var>callbacks</var>.
 </ol>
+</div>
 
 
 <h3 id=dispatching-events>Dispatching events</h3>
 
+<div algorithm>
 <p>To <dfn export id=concept-event-dispatch>dispatch</dfn> an <var>event</var> to a
 <var>target</var>, with an optional <var>legacy target override flag</var> and an optional
 <var>legacyOutputDidListenersThrowFlag</var>, run these steps:
@@ -1468,7 +1485,9 @@ property of the event being dispatched.
 
  <li><p>Return false if <var>event</var>'s <a>canceled flag</a> is set; otherwise true.
 </ol>
+</div>
 
+<div algorithm>
 <p>To <dfn noexport id=concept-event-path-append>append to an event path</dfn>, given an
 <var>event</var>, <var>invocationTarget</var>, <var>shadowAdjustedTarget</var>,
 <var>relatedTarget</var>, <var>touchTargets</var>, and a <var>slot-in-closed-tree</var>, run these
@@ -1494,7 +1513,9 @@ steps:</p>
  <a for=Event/path>root-of-closed-tree</a> is <var>root-of-closed-tree</var>, and
  <a for=Event/path>slot-in-closed-tree</a> is <var>slot-in-closed-tree</var>.
 </ol>
+</div>
 
+<div algorithm>
 <p>To <dfn noexport id=concept-event-listener-invoke>invoke</dfn>, given a <var>struct</var>,
 <var>event</var>, <var>phase</var>, and an optional <var>legacyOutputDidListenersThrowFlag</var>,
 run these steps:
@@ -1559,7 +1580,9 @@ run these steps:
    <li><p>Set <var>event</var>'s {{Event/type}} attribute value to <var>originalEventType</var>.
   </ol>
 </ol>
+</div>
 
+<div algorithm>
 <p>To <dfn noexport id=concept-event-listener-inner-invoke>inner invoke</dfn>, given an
 <var>event</var>, <var>listeners</var>, <var>phase</var>, <var>invocationTargetInShadowTree</var>,
 and an optional <var>legacyOutputDidListenersThrowFlag</var>, run these steps:
@@ -1633,10 +1656,12 @@ and an optional <var>legacyOutputDidListenersThrowFlag</var>, run these steps:
 
  <li><p>Return <var>found</var>.
 </ol>
+</div>
 
 
 <h3 id=firing-events>Firing events</h3>
 
+<div algorithm>
 <p>To <dfn export id=concept-event-fire>fire an event</dfn> named <var>e</var> at <var>target</var>,
 optionally using an <var>eventConstructor</var>, with a description of how IDL attributes are to be
 initialized, and a <var>legacy target override flag</var>, run these steps:
@@ -1659,6 +1684,7 @@ initialized, and a <var>legacy target override flag</var>, run these steps:
  <li><p>Return the result of <a>dispatching</a> <var>event</var> at <var>target</var>, with
  <var>legacy target override flag</var> set if set.
 </ol>
+</div>
 
 <p class=note>Fire in the context of DOM is short for
 <a lt="create an event">creating</a>, initializing, and <a>dispatching</a> an <a>event</a>.