minor #4961 Assert all project source files are monolithic. (SpacePossum)
minor #4961 Assert all project source files are monolithic. (SpacePossum)

This PR was merged into the 2.15 branch.

Discussion
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Assert all project source files are monolithic.

Commits
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39f127da Assert all project source and test files contain a single classy.

GrahamCampbell/PHP-CS-Fixer,keradus/PHP-CS-Fixer,GrahamCampbell/PHP-CS-Fixer,kubawerlos/PHP-CS-Fixer,gharlan/PHP-CS-Fixer,gharlan/PHP-CS-Fixer,FriendsOfPHP/PHP-CS-Fixer,kubawerlos/PHP-CS-Fixer,Slamdunk/PHP-CS-Fixer,Slamdunk/PHP-CS-Fixer,FriendsOfPHP/PHP-CS-Fixer,SpacePossum/PHP-CS-Fixer,SpacePossum/PHP-CS-Fixer,keradus/PHP-CS-Fixer