patch 8.2.4566: check for existing buffer in session file may not work

Problem:    Check for existing buffer in session file does not work for files
            in the home directory.
Solution:   Use fnamemodify(). (James Cherti, closes #9945)  Add a test.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4566,
 /**/
     4565,
 /**/