Fix generation of Blame url

The Blame URLs returned by `url_for` currently return e.g. `b'master'`
for the ref component, breaking the "Blame" tab. Example:

https://git.sr.ht/~yyny/test/blame/b%27master%27/README.md

This patch fixes that.

gitsrht/blueprints/repo.py

@@ -416,7 +416,7 @@ def weld_hunks(blame):
         yield last
 
 @repo.route("/<owner>/<repo>/blame/<path:ref>", defaults={"path": ""})
-@repo.route("/<owner>/<repo>/blame/<ref>/<path:path>")
+@repo.route("/<owner>/<repo>/blame/<path:ref>/<path:path>")
 def blame(owner, repo, ref, path):
     owner, repo = get_repo_or_redir(owner, repo)
     with GitRepository(repo.path) as git_repo: