fix: "Follow symlink" to work with arbitrary links (#12246)

This change introduces a Path method on the TreeEntry struct, that
collects the path by moving upwards in the tree.

The existing FollowSymlink(s) methods interface has been changed, the
previously returned string has been removed, as after the fix it wasn't
used anywhere.

Fixes: #9931

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/12246
Reviewed-by: Gusted <gusted@noreply.codeberg.org>

modules/base/tool.go

@@ -103,7 +103,7 @@ func Int64sToStrings(ints []int64) []string {
 func EntryIcon(entry *git.TreeEntry) string {
 	switch {
 	case entry.IsLink():
-		te, _, err := entry.FollowLink()
+		te, err := entry.FollowLink()
 		if err != nil {
 			log.Debug(err.Error())
 			return "file-symlink-file"