fish: Autocomplete 'sparse' command (RHBZ#582899).

I also rechecked the list of built-in commands against
the actual commands to make sure no others were omitted.

fish/fish.h

@@ -125,6 +125,7 @@ extern char *try_tilde_expansion (char *path);
   "glob",				\
   "more", "less",			\
   "reopen",				\
+  "sparse",                             \
   "time"
 
 static inline char *