Regex Tester & Validator

Matches markdown note lines beginning with the bold label 'NOTE: ' followed by italic text wrapped in underscores (e.g. NOTE: _this is important_). The first capture group holds the note prefix, and the second captures the italic content, which cannot contain underscores. Used with global and multiline flags, it's ideal for extracting, validating, or restyling underscore-based italic notes across an entire markdown document.