docs: mention handlebars escaping

docs/usage/configuration-options.md

@@ -1294,7 +1294,7 @@ Users can define custom managers for cases such as:
 
 The custom manager concept is based on using Regular Expression named capture groups. For the fields `datasource`, `depName` and `currentValue`, it's mandatory to have either a named capture group matching them (e.g. `(?<depName>.*)`) or to configure it's corresponding template (e.g. `depNameTemplate`). It's not recommended to do both, due to the potential for confusion. It is recommended to also include `versioning` however if it is missing then it will default to `semver`.
 
-For more details and examples, see the documentation page the for the regex manager [here](/modules/manager/regex/).
+For more details and examples, see the documentation page the for the regex manager [here](/modules/manager/regex/). For template fields, use the triple brace `{{{ }}}` notation to avoid `handlebars` escaping any special characters.
 
 ### matchStrings
 

lib/datasource/repology/readme.md

@@ -20,7 +20,7 @@ A real world example for this specific datasource would be maintaining system pa
       "matchStrings": [
         "#\\s*renovate:\\s*datasource=(?<datasource>.*?) depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\sENV .*?_VERSION=(?<currentValue>.*)\\s"
       ],
-      "versioningTemplate": "{{#if versioning}}{{versioning}}{{else}}semver{{/if}}"
+      "versioningTemplate": "{{#if versioning}}{{{versioning}}}{{else}}semver{{/if}}"
     }
   ]
 }

lib/manager/regex/readme.md

@@ -84,7 +84,7 @@ The above (obviously not a complete `Dockerfile`, but abbreviated for this examp
       "matchStrings": [
         "datasource=(?<datasource>.*?) depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\sENV .*?_VERSION=(?<currentValue>.*)\\s"
       ],
-      "versioningTemplate": "{{#if versioning}}{{versioning}}{{else}}semver{{/if}}"
+      "versioningTemplate": "{{#if versioning}}{{{versioning}}}{{else}}semver{{/if}}"
     },
     {
       "fileMatch": ["^Dockerfile$"],
@@ -97,6 +97,6 @@ The above (obviously not a complete `Dockerfile`, but abbreviated for this examp
 }
 ```
 
-In the above the `versioningTemplate` is not actually necessary because Renovate already defaults to `semver` versioning, but it has been included to help illustrate why we call these fields _templates_. They are named this way because they are compiled using `handlebars` and so can be composed from values you collect in named capture groups.
+In the above the `versioningTemplate` is not actually necessary because Renovate already defaults to `semver` versioning, but it has been included to help illustrate why we call these fields _templates_. They are named this way because they are compiled using `handlebars` and so can be composed from values you collect in named capture groups. You will usually want to use the tripe brace `{{{ }}}` template (e.v. `{{{versioniong}}}` to be safe because `handlebars` escapes special characters by default with double braces.
 
 By adding the comments to the `Dockerfile`, you can see that instead of four separate `regexManagers` being required, there is now only one - and the `Dockerfile` itself is now somewhat better documented too. The syntax we used there is completely arbitrary and you may choose your own instead if you prefer - just be sure to update your `matchStrings` regex.