Feature Request: Add regex_search to Matches

Right now matches only works on the whole word, functionality should be added to allow search similar to regex_search.

Begin by locating the Matches implementation and its tests, then inspect how the current whole-word matching behavior is defined. Compare this with the project's existing regex_search behavior. Done means Matches supports the requested regex-style search and the expected behavior is covered by tests.

Written by the indexing model from the issue text.