Add /me slaps <nick> support

Comes with bonus extra refactoring I can't be bothered to `git commit
--amend` into my earlier prep work. Besides, `formatting.plain()` *was*
only called once, so it wasn't redundant yet. :P

sopel_slap/plugin.py

@@ -10,7 +10,7 @@
 """
 from __future__ import annotations
 
-from sopel import formatting, plugin
+from sopel import plugin
 
 from .util import slap
 
@@ -22,7 +22,18 @@ def slap_command(bot, trigger):
 
     if target is None:
         target = trigger.nick
-    else:
-        target = formatting.plain(target)
+
+    return slap(bot, trigger, target)
+
+
+@plugin.ctcp('ACTION')
+@plugin.rule(r'^slaps (\w+)$')
+def slap_action(bot, trigger):
+    """Slap someone using the power of CTCP ACTION."""
+    target = trigger.group(1)
+
+    if target is None:
+        # no self-slaps via /me; just fail silently
+        return plugin.NOLIMIT
 
     return slap(bot, trigger, target)

sopel_slap/util.py

@@ -11,7 +11,7 @@
 import random
 from typing import TYPE_CHECKING
 
-from sopel import tools
+from sopel import formatting, tools
 
 if TYPE_CHECKING:
     from sopel.bot import SopelWrapper
@@ -31,6 +31,9 @@
 
 def slap(bot: SopelWrapper, trigger: Trigger, target: str):
     """Do the slapping."""
+    # the target could contain formatting control codes, so strip those
+    target = formatting.plain(target)
+
     # ensure target is an Identifier to increase reliability of "is nick" check
     if not isinstance(target, tools.Identifier):
         if hasattr(bot, 'make_identifier'):