Adjust coding standards to always omit parenthesis for include/require statements

[desrosj]

This is a follow-up of #48082 and the changes committed in [47198].

Now that all parenthesis have been removed from include/include_once/require/require_once statements, the PHCS configuration file should also be updated to enforce this until the sniff is moved from the WordPress-Extra ruleset to the WordPress-Core ruleset upstream in the ​WordPress Coding Standards repo (pull request coming soon).

Running this sniff on trunk today produces 4 errors, all of them are instances where two spaces are included after return and echo statements instead of one. These instances are all typos and should be fixed.

The PHP coding standards in the handbook should also be updated to reflect that parenthesis should be omitted, and one space and one space only should follow these language constructs to satisfy this check.

[desrosj]

49376.2.diff​ adds the rules for parenthesis that I missed in the first patch.

[GaryJ]

The Squiz.WhiteSpace.LanguageConstructSpacing sniff is deprecated and ​will be removed in PHPCS 4.0.

Consider using Generic.WhiteSpace.LanguageConstructSpacing instead. Though, since this change is intended as a temporary one until WPCS itself changes (which should happen before PHPCS 4.0), leave as is.

[jrf]

LGTM

And yes, leave the LanguageContructSpacing one as is. Once it's moved in WPCS (and a new WPCS version released), these rules can be removed and that should be soon enough.
WPCS will then take care of the sniff change-over automatically if and when.

[SergeyBiryukov]

In 47207:

Coding Standards: Adjust coding standards to always omit parentheses for include/require statements.

These are language constructs, not function calls, so the parentheses are unnecessary.

This updates the PHPCS configuration file the enforce the sniff until it is moved from the WordPress-Extra ruleset to the WordPress-Core ruleset upstream.

Follow-up to [47198].

Props desrosj, jrf, GaryJ.
Fixes #49376.