Generic/OpeningFunctionBraceKernighanRitchie: improve error message

Follow up on 707

When there are multiple tabs between the end of the function signature and the open brace, the "found: $length" part of the error message would refer to the number of tabs found.

This is inconsistent with other sniffs and confusing.

This commit fixes this, while still maintaining the previous behaviour - as introduced via squizlabs/PHP_CodeSniffer@c4b9807 - of special casing the messaging for a single tab - independently of whether or not tab replacement is in effect.

Example for line 10 of test case file 2:
```
// Before:
Expected 1 space before opening brace; found 3

// After:
Expected 1 space before opening brace; found 11
```

Covered via pre-existing tests in both test case files + some additional new tests.

Author: jrfnl

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

@@ -138,22 +138,26 @@ public function process(File $phpcsFile, $stackPtr)
             return;
         }
 
-        // We are looking for tabs, even if they have been replaced, because
-        // we enforce a space here.
-        if (isset($tokens[($openingBrace - 1)]['orig_content']) === true) {
-            $spacing = $tokens[($openingBrace - 1)]['orig_content'];
-        } else {
-            $spacing = $tokens[($openingBrace - 1)]['content'];
-        }
-
+        // Enforce a single space. Tabs not allowed.
+        $spacing = $tokens[($openingBrace - 1)]['content'];
         if ($tokens[($openingBrace - 1)]['code'] !== T_WHITESPACE) {
             $length = 0;
         } else if ($spacing === "\t") {
+            // Tab without tab-width set, so no tab replacement has taken place.
             $length = '\t';
         } else {
             $length = strlen($spacing);
         }
 
+        // If tab replacement is on, avoid confusing the user with a "expected 1 space, found 1"
+        // message when the "1" found is actually a tab, not a space.
+        if ($length === 1
+            && isset($tokens[($openingBrace - 1)]['orig_content']) === true
+            && $tokens[($openingBrace - 1)]['orig_content'] === "\t"
+        ) {
+            $length = '\t';
+        }
+
         if ($length !== 1) {
             $error = 'Expected 1 space before opening brace; found %s';
             $data  = [$length];

src/Standards/Generic/Tests/Functions/OpeningFunctionBraceKernighanRitchieUnitTest.2.inc

@@ -9,3 +9,11 @@ function myFunction()	{
 // Uses three tabs.
 function myFunction()			{
 }
+
+// Uses one tab in a way that it translates to exactly one space with tab replacement.
+function oneT()	{
+}
+
+// Mixed tabs and spaces.
+function mixed()	  	{
+}

src/Standards/Generic/Tests/Functions/OpeningFunctionBraceKernighanRitchieUnitTest.2.inc.fixed

@@ -9,3 +9,11 @@ function myFunction() {
 // Uses three tabs.
 function myFunction() {
 }
+
+// Uses one tab in a way that it translates to exactly one space with tab replacement.
+function oneT() {
+}
+
+// Mixed tabs and spaces.
+function mixed() {
+}

src/Standards/Generic/Tests/Functions/OpeningFunctionBraceKernighanRitchieUnitTest.php

@@ -88,6 +88,8 @@ public function getErrorList($testFile='')
             return [
                 6  => 1,
                 10 => 1,
+                14 => 1,
+                18 => 1,
             ];
         default:
             return [];