message: Fix syntax highlighting for multi-digit registers
  The pattern for immediates would interfere with the register pattern.
  Fixed by requiring that immediates are prepended by a word boundary character.
diff: @@ -105,6 +105,12 @@ SyntaxHighlighter::SyntaxHighlighter(QTextDocument* parent) : QSyntaxHighlighter
  m_highlightingRules.append(rule);
  }
  + // Create rules for registers that can easily be regex matched
  + // (saved, temporary and argument registers)
  + rule.pattern = QRegularExpression("\\b[(a|s|t|x)][0-9]{1,2}");
  + rule.format = regFormat;
  + m_highlightingRules.append(rule);
  +
  // Create match cases for instructions
  QStringList instructionPatterns;
  instructionPatterns << "\\bla\\b"
  @@ -203,15 +209,9 @@ SyntaxHighlighter::SyntaxHighlighter(QTextDocument* parent) : QSyntaxHighlighter
  m_highlightingRules.append(rule);
  }
  - // Create rules for registers that can easily be regex matched
  - // (saved, temporary and argument registers)
  - rule.pattern = QRegularExpression("\\b[(a|s|t|x)][0-9]{1,2}");
  - rule.format = regFormat;
  - m_highlightingRules.append(rule);
  -
  // Create immediate hightlighting rule
  immFormat.setForeground(QColor(Qt::darkGreen));
  - rule.pattern = QRegularExpression("(?<![A-Za-z])[-+]?\\d+");
  + rule.pattern = QRegularExpression("\\b(?<![A-Za-z])[-+]?\\d+");
  rule.format = immFormat;
  m_highlightingRules.append(rule);
  