Test, validate and match regular expressions
Matches the beginning of each paragraph in text, where a paragraph starts after two or more consecutive line breaks (CRLF, CR, or LF), one or more Unicode paragraph separators (\p{Zp}), or at the very start of input, provided the line starts with a non-whitespace character. Ideal for counting, splitting, or iterating paragraphs in .NET with Unicode-aware delimiters. Group 1 captures the preceding delimiter.