bash : add autocomplete for checksum.

document/linux/config/bash/module/autocomplete.sh

@@ -1,3 +1,6 @@
+# bash autocomplete.
+# usage: complete -F _foo foo
+# there are also options like -o nospace. see man for more info.
 autocomplete()
 {
   local commands="$@"

document/linux/config/bash/module/checksum.sh

@@ -25,3 +25,11 @@ checksum()
   echo "supported actions: new (n), check (c)."
   return 1
 }
+
+# autocomplete.
+_checksum()
+{
+  autocomplete "{new,check}"
+}
+
+complete -F _checksum checksum