Generic/OpeningFunctionBraceKernighanRichie: improve handling of tabs

This commit makes a tiny performance improvement to the sniff when
handling fixing code with tabs. Before this change, the sniff would need
two passes of the fixer for code with one tab before the opening brace.
First, it would add a space between the tab and the opening brace. Then,
on a second pass, it would replace the tab and the space with just one
space.

Now, it replaces the tab with the space directly without the need for a
second pass.

src/Standards/Generic/Sniffs/Functions/OpeningFunctionBraceKernighanRitchieSniff.php

@@ -167,7 +167,7 @@ public function process(File $phpcsFile, $stackPtr)
             $data  = [$length];
             $fix   = $phpcsFile->addFixableError($error, $openingBrace, 'SpaceBeforeBrace', $data);
             if ($fix === true) {
-                if ($length === 0 || $length === '\t') {
+                if ($length === 0) {
                     $phpcsFile->fixer->addContentBefore($openingBrace, ' ');
                 } else {
                     $phpcsFile->fixer->replaceToken(($openingBrace - 1), ' ');