[9.x] Allow @class() for component tags

[aguingand]

Closes #42977. Example of use:

<x-icon @class(['lg' => $large]) />

Description

My attempt to allow @class() directive alongside component tag attributes. I've adapted the regex used for statements in the blade compiler.

I have made 2 choices in this PR:

• The regex only match the statement class with an expression. Because it's the only one allowed here, it's seems more comprehensible instead of compiling the component and ignoring not handled directives.
• Double quotes are naively converted to single quotes inside the directive expression. Since we compile to :class="...", double quotes would break the compiled code.

[taylorotwell]

Do we convert double quotes to single quotes in other places in this way?

[aguingand]

@taylorotwell I don't think so. The same problem exists for {{ $attributes }} parsing, e.g.

<x-icon {{ $attributes->class("test") }} /> {{-- double quotes breaks compiled code --}}

framework/src/Illuminate/View/Compilers/ComponentTagCompiler.php

Line 554 in ca6a928

return preg_replace($pattern, ' :attributes="$1"', $attributeString);

I have no opinion here, it looks like a bug but maybe a warning in the docs is enough.

[taylorotwell]

Thanks!