[TwigComponent] Restrict anonymous component lookup to Twig files in debug command

[squrious]

Q	A
Bug fix?	yes
New feature?	no
Issues
License	MIT

Hi!

The debug:twig-component command looks for files in the anonymous template directory, but fails if some files are actually not Twig components (like .md).

For example, with a README.md file in templates/components:

$ php bin/console debug:twig-component 
[critical] Error thrown while running command "debug:twig-component". Message: "Unknown component "README.md". And no matching anonymous component template was found."

In ComponentFactory.php line 254:
                                                                                          
  Unknown component "README.md". And no matching anonymous component template was found.  
                                                                                          

debug:twig-component [<name>]

This PR restricts the finder to *.html.twig files, so others are ignored.

[smnandre]

Maybe add a case in TwigComponentDebugTest that check NotAComponent is not listed ?

(like the testWithNoMatchComponent test ?)

[squrious]

Done :)

[smnandre]

Thank you @squrious ! 😄

[kbond]

Thank you Nicolas.