Added rule for fixing Alt+Space character

Happens on the Mac a lot when typing a pipe character (Alt+7), and
keeping the Alt key pressed down for a bit too long, so instead of
Space, you're typing Alt+Space. This rule replaces the Alt+Space with a
simple Space character.

$ ps -ef | grep foo
-bash:  grep: command not found
$ fuck
ps -ef | grep foo

README.md

@@ -157,6 +157,7 @@ using matched rule and run it. Rules enabled by default:
 * `brew_unknown_command` – fixes wrong brew commands, for example `brew docto/brew doctor`;
 * `cd_parent` – changes `cd..` to `cd ..`;
 * `cp_omitting_directory` – adds `-a` when you `cp` directory;
+* `fix_alt_space` – replaces Alt+Space with Space character;
 * `git_no_command` – fixes wrong git commands like `git brnch`;
 * `git_push` – adds `--set-upstream origin $branch` to previous failed `git push`;
 * `has_exists_script` – prepends `./` when script/binary exists;