Use the type RefName for all the needed places and fix pull mirror sync bugs (#24634)

This PR replaces all string refName as a type `git.RefName` to make the
code more maintainable.

Fix #15367
Replaces #23070 
It also fixed a bug that tags are not sync because `git remote --prune
origin` will not remove local tags if remote removed.

We in fact should use `git fetch --prune --tags origin` but not `git
remote update origin` to do the sync.

Some answer from ChatGPT as ref.

> If the git fetch --prune --tags command is not working as expected,
there could be a few reasons why. Here are a few things to check:
> 
>Make sure that you have the latest version of Git installed on your
system. You can check the version by running git --version in your
terminal. If you have an outdated version, try updating Git and see if
that resolves the issue.
> 
>Check that your Git repository is properly configured to track the
remote repository's tags. You can check this by running git config
--get-all remote.origin.fetch and verifying that it includes
+refs/tags/*:refs/tags/*. If it does not, you can add it by running git
config --add remote.origin.fetch "+refs/tags/*:refs/tags/*".
> 
>Verify that the tags you are trying to prune actually exist on the
remote repository. You can do this by running git ls-remote --tags
origin to list all the tags on the remote repository.
> 
>Check if any local tags have been created that match the names of tags
on the remote repository. If so, these local tags may be preventing the
git fetch --prune --tags command from working properly. You can delete
local tags using the git tag -d command.

---------

Co-authored-by: delvh <dev.lh@web.de>

services/webhook/matrix.go

@@ -73,7 +73,7 @@ func MatrixLinkFormatter(url, text string) string {
 
 // MatrixLinkToRef Matrix-formatter link to a repo ref
 func MatrixLinkToRef(repoURL, ref string) string {
-	refName := git.RefEndName(ref)
+	refName := git.RefName(ref).ShortName()
 	switch {
 	case strings.HasPrefix(ref, git.BranchPrefix):
 		return MatrixLinkFormatter(repoURL+"/src/branch/"+util.PathEscapeSegments(refName), refName)
@@ -95,7 +95,7 @@ func (m *MatrixPayload) Create(p *api.CreatePayload) (api.Payloader, error) {
 
 // Delete composes Matrix payload for delete a branch or tag.
 func (m *MatrixPayload) Delete(p *api.DeletePayload) (api.Payloader, error) {
-	refName := git.RefEndName(p.Ref)
+	refName := git.RefName(p.Ref).ShortName()
 	repoLink := MatrixLinkFormatter(p.Repo.HTMLURL, p.Repo.FullName)
 	text := fmt.Sprintf("[%s:%s] %s deleted by %s", repoLink, refName, p.RefType, p.Sender.UserName)