Generic/UnnecessaryHeredoc: bug fix - stray backslashes after fixing

If the original heredoc contained an escaped variable or an escaped backslash (neither of which need heredoc), the nowdoc version of the text string would contain stray backslashes as these escapes are not needed in nowdocs, so would be interpreted as literals.

Fixed now.

Includes tests.

Author: jrfnl

src/Standards/Generic/Sniffs/Strings/UnnecessaryHeredocSniff.php

@@ -85,10 +85,22 @@ public function process(File $phpcsFile, $stackPtr)
 
         $fix = $phpcsFile->addFixableWarning($warning, $stackPtr, 'Found');
         if ($fix === true) {
+            $phpcsFile->fixer->beginChangeset();
+
             $identifier  = trim(ltrim($tokens[$stackPtr]['content'], '<'));
             $replaceWith = "'".trim($identifier, '"')."'";
             $replacement = str_replace($identifier, $replaceWith, $tokens[$stackPtr]['content']);
             $phpcsFile->fixer->replaceToken($stackPtr, $replacement);
+
+            for ($i = ($stackPtr + 1); $i < $closer; $i++) {
+                $content = $tokens[$i]['content'];
+                $content = str_replace(['\\$', '\\\\'], ['$', '\\'], $content);
+                if ($tokens[$i]['content'] !== $content) {
+                    $phpcsFile->fixer->replaceToken($i, $content);
+                }
+            }
+
+            $phpcsFile->fixer->endChangeset();
         }
 
     }//end process()

src/Standards/Generic/Tests/Strings/UnnecessaryHeredocUnitTest.1.inc

@@ -104,5 +104,5 @@ END;
 $heredoc = <<< "END"
 some text
 some \$text
-some text
+some text \\ including a backslash
 END;

src/Standards/Generic/Tests/Strings/UnnecessaryHeredocUnitTest.1.inc.fixed

@@ -103,6 +103,6 @@ END;
 
 $heredoc = <<< 'END'
 some text
-some \$text
-some text
+some $text
+some text \ including a backslash
 END;

src/Standards/Generic/Tests/Strings/UnnecessaryHeredocUnitTest.2.inc

@@ -104,5 +104,5 @@ $heredoc = <<<END
 $heredoc = <<< "END"
     some text
     some \$text
-    some text
+    some text \\ including a backslash
     END;

src/Standards/Generic/Tests/Strings/UnnecessaryHeredocUnitTest.2.inc.fixed

@@ -103,6 +103,6 @@ $heredoc = <<<'END'
 
 $heredoc = <<< 'END'
     some text
-    some \$text
-    some text
+    some $text
+    some text \ including a backslash
     END;