minor #18143 [Standards] Remove additional comma (alexandre-daubois)

This PR was merged into the 5.4 branch.

Discussion
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[Standards] Remove additional comma

DOCtor-RST is unhappy about backticks escaping (see the failing CI task).
Wanted to fix it as well but the documentation rendered successfully in https://symfony.com/doc/current/contributing/code/standards.html, so I'm not sure we should take this warning in account 🤔

Commits
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c6a4e45 [Standards] Remove additional comma

Author: OskarStark

contributing/code/standards.rst

@@ -179,9 +179,14 @@ Structure
 
 * Exception and error message strings must be concatenated using :phpfunction:`sprintf`;
 
-* Exception and error messages must not contain backticks (e.g. 'The \`foo\` option ...'),
+* Exception and error messages must not contain backticks,
   even when referring to a technical element (such as a method or variable name).
-  Double quotes must be used at all time (e.g. 'The "foo" option ...'),;
+  Double quotes must be used at all time:
+
+  .. code-block:: diff
+
+    - Expected `foo` option to be one of ...
+    + Expected "foo" option to be one of ...
 
 * Exception and error messages must start with a capital letter and finish with a dot ``.``;