Fix logical XOR

The '^' is the bitwise XOR, we should use logical XOR in
these contexts. The operator!=() should serve for it.

More info and reasoning:
https://stackoverflow.com/questions/24542

Change-Id: I1bd70bdcab25455f409594f0f14c209d1de11d18
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/texteditor/highlighter.cpp

@@ -299,7 +299,8 @@ void Highlighter::highlightBlock(const QString &text)
         TextBlockUserData *data = TextDocumentLayout::userData(nextBlock);
         if (data->syntaxState() != state) {
             data->setSyntaxState(state);
-            setCurrentBlockState(currentBlockState() ^ 1); // force rehighlight of next block
+            // Toggles the LSB of current block's userState. It forces rehighlight of next block.
+            setCurrentBlockState(currentBlockState() ^ 1);
         }
         data->setFoldingIndent(TextDocumentLayout::braceDepth(block));
     }