Get aspell --mode completions from 'aspell modes' output.

CHANGES

@@ -1,7 +1,7 @@
 bash-completion (2.x)
 
   [ Ville Skyttä ]
-  * Improve gendiff and smartctl completions.
+  * Improve aspell, gendiff, and smartctl completions.
   * Try harder to find the correct perl executable to run the perl helper with.
   * Drop rpm query support for rpm < 4.1.
   * Split rpm and rpmbuild completions and improve them both.

completions/aspell

@@ -37,7 +37,8 @@ _aspell()
             return 0
             ;;
         --mode)
-            COMPREPLY=( $( compgen -W 'none url email sgml tex' -- "$cur" ) )
+            COMPREPLY=( $( compgen -W "$( $1 modes 2>/dev/null | \
+                awk '{ print $1 }' )" -- "$cur" ) )
             return 0
             ;;
         --sug-mode)