updated for version 7.3.901

Problem:    Outdated comment, ugly condition.
Solution:   Update a few comments, break line.

src/misc1.c

@@ -5054,7 +5054,6 @@ vim_fnamencmp(x, y, len)
     int		cx = NUL;
     int		cy = NUL;
 
-    /* TODO: multi-byte characters. */
     while (len > 0)
     {
 	cx = PTR2CHAR(px);