Fix issue regarding failing test cases

groups.pop() was called without considering the
number of capturing groups within. This caused
some issues with the end bound of word matching
being popped and removed from the array.

packages/core/src/lib/markdown-it/highlight/HighlightRuleComponent.ts

@@ -43,15 +43,21 @@ export class HighlightRuleComponent {
     const linesliceWordMatch = compString.match(LINESLICE_WORD_REGEX);
     const sliceMatch = linesliceCharMatch || linesliceWordMatch;
     if (sliceMatch) {
-      // There are four capturing groups: [full match, line number, start bound, end bound]
+      // There are four/five capturing groups: [full match, line number, start bound,
+      //                                        end bound,highlight spaces]
       const groups = sliceMatch.slice(1); // discard full match
 
       const lineNumber = HighlightRuleComponent
         .isValidLineNumber(groups.shift() ?? '', 1, lines.length, lineNumberOffset);
       if (!lineNumber) return null;
 
+      let highlightSpaces = false;
+      if (sliceMatch === linesliceCharMatch) {
+        highlightSpaces = groups.pop() === '+';
+      }
+
       const isUnbounded = groups.every(x => x === '');
-      const highlightSpaces = groups.pop() === '+';
+
       if (isUnbounded) {
         return new HighlightRuleComponent(lineNumber, true, []);
       }