worktree_git_path(): move the declaration to path.h

The definition of this function is in path.c but its declaration is
in worktree.h, which is something unexpected.  The function is
explained as "Similar to git_path()"; declaring it next to where
git_path() is declared would make more sense.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.c

@@ -29,6 +29,7 @@
 #include "bisect.h"
 #include "packfile.h"
 #include "worktree.h"
+#include "path.h"
 #include "read-cache.h"
 #include "setup.h"
 #include "sparse-index.h"