matcher: do not prepend '.*' to pattern using ^ after flags Since the previous commit (fixing wider issue), the code generated strange regex. This is now fixed and tested.

matcher: fix the issue with regex inline-flag in rust oo Same problem same solution.

matcher: fix issues regex flag contained in pattern (issue6759) Python 3.11 is now enforcing that flag must be at the beginning of the regex This creates a serious regression for people using Python 3.11 with an hgignore using flag in a "relre" pattern. We now detect any flags in such pattern and "prepend" our ".*" pattern after them. In addition, we now insert the flag in the regexp to only affect the pattern we are rewriting. Otherwise, the regex built from the combined pattern would these flags in the middle of it anyway. As a side effect of this last change, we fix a bug… before this change regex flag in a pattern would affect all combined patterns. That was bad and is not longer the case. The Rust code needs to be updated to fix that very bug, but we will do it in another changeset.