fix: Namespace-relative names for PHP

[mkslanc]

Issue #, if available:

Description of changes:
Changed regexp's order to determine namespace\NamespaceName as T_NAME_RELATIVE and not T_NAMESPACE + T_NAME_FULLY_QUALIFIED (according to new RFC)

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

Base: 86.06% // Head: 86.06% // No change to project coverage 👍

Coverage data is based on head (e37170d) compared to base (cd2de86).
Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4963   +/-   ##
=======================================
  Coverage   86.06%   86.06%           
=======================================
  Files         544      544           
  Lines       41432    41432           
  Branches     6537     6537           
=======================================
  Hits        35659    35659           
  Misses       5773     5773           

Flag	Coverage Δ
unittests	86.06% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.