minor #6618 Added a note about coding standards and method arguments (javiereguiluz)

This PR was submitted for the 2.3 branch but it was merged into the 2.7 branch instead (closes #6618).

Discussion
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Added a note about coding standards and method arguments

This coding standard is optional in the PSR-2 standard, so we must explain our own convention. Related to symfony/symfony#18890.

Commits
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b7429a5 Added a note about coding standards and method arguments

Author: xabbuh

contributing/code/standards.rst

@@ -153,13 +153,19 @@ Structure
   that are not intended to be instantiated from the outside and thus are not
   concerned by the `PSR-0`_ and `PSR-4`_ autoload standards;
 
+* Declare the class inheritance and all the implemented interfaces on the same
+  line as the class name;
+
 * Declare class properties before methods;
 
 * Declare public methods first, then protected ones and finally private ones.
   The exceptions to this rule are the class constructor and the ``setUp`` and
   ``tearDown`` methods of PHPUnit tests, which should always be the first methods
   to increase readability;
 
+* Declare all the arguments on the same line as the method/function name, no
+  matter how many arguments there are;
+
 * Use parentheses when instantiating classes regardless of the number of
   arguments the constructor has;