commit: clean up filename parsing constants

Just use literals. The code is much cleaner.
4 jobs for cleanups
Status Job ID Name Coverage
  External
passed ghostflow-check-master

passed rust-git-checks-rustdash-linux-debug

00:00:14

passed rust-git-checks-rustdash-linux-debug+latest

00:00:13

failed rust-git-checks-rustdash-linux-debug+minver

00:00:01