ui-tree: move set_title_from_path to ui-shared

The ui-blame code will also need to call set_title_from_path, so go
ahead and move it to ui-shared.

Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Reviewed-by: John Keeping <john@keeping.me.uk>

ui-shared.h

@@ -77,4 +77,6 @@ extern void cgit_print_snapshot_links(const char *repo, const char *head,
 				      const char *hex, int snapshots);
 extern void cgit_add_hidden_formfields(int incl_head, int incl_search,
 				       const char *page);
+
+extern void cgit_set_title_from_path(const char *path);
 #endif /* UI_SHARED_H */