patch 9.1.0565: Stop directory doesn't work properly in 'tags'

Problem:  Stop directory doesn't work properly in 'tags'.
          (Jesse Pavel)
Solution: Also move the stop directory forward by one byte.
          (zeertzjq)

This doesn't support relative stop directories yet, as they are not
supported in other places like findfile() either.

fixes: #15200
related: #15202

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/tag.c

@@ -3412,6 +3412,11 @@ get_tagfname(
 	    // move the filename one char forward and truncate the
 	    // filepath with a NUL
 	    filename = gettail(buf);
+	    if (r_ptr != NULL)
+	    {
+		STRMOVE(r_ptr + 1, r_ptr);
+		++r_ptr;
+	    }
 	    STRMOVE(filename + 1, filename);
 	    *filename++ = NUL;