Bidirectional Class - Nonspacing Mark

Nonspacing Mark is a category for characters that combine with a preceding base character without adding any width of their own, often altering its pronunciation or meaning, such as accent marks, vowel signs, or diacritics. In the bidirectional algorithm, these marks are treated as neutral, meaning they do not inherently carry a left-to-right or right-to-left direction. Instead, they inherit the directional context of the surrounding text, typically taking on the direction of the base character they modify. This ensures that combining marks do not disrupt the overall reading order, especially in mixed-script texts where they might appear between or after letters from different directional systems. Their behavior is crucial for correctly displaying scripts like Arabic or Hebrew, where vowel points and other marks must sit accurately relative to the base consonant without causing unintended line breaks or reordering.