Refactor various strings (#17784)

Fixes #16478

Co-authored-by: Gusted <williamzijl7@hotmail.com>

Co-authored-by: Gusted <williamzijl7@hotmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/git/repo_ref_nogogit.go

@@ -66,7 +66,7 @@ func (repo *Repository) GetRefsFiltered(pattern string) ([]*Reference, error) {
 		refName = refName[:len(refName)-1]
 
 		// refName cannot be HEAD but can be remotes or stash
-		if strings.HasPrefix(refName, "/refs/remotes/") || refName == "/refs/stash" {
+		if strings.HasPrefix(refName, RemotePrefix) || refName == "/refs/stash" {
 			continue
 		}