Generic/UnnecessaryFinalModifier: make the sniff more efficient

No need to token walk the contents of functions as the `final` keyword cannot be used in them anyway.

Author: jrfnl

src/Standards/Generic/Sniffs/CodeAnalysis/UnnecessaryFinalModifierSniff.php

@@ -73,6 +73,13 @@ public function process(File $phpcsFile, $stackPtr)
                 $error = 'Unnecessary FINAL modifier in FINAL class';
                 $phpcsFile->addWarning($error, $next, 'Found');
             }
+
+            // Skip over the contents of functions as those can't contain the `final` keyword anyway.
+            if ($tokens[$next]['code'] === T_FUNCTION
+                && isset($tokens[$next]['scope_closer']) === true
+            ) {
+                $next = $tokens[$next]['scope_closer'];
+            }
         }
 
     }//end process()