Prevent middle-word-em from running if MWE's allowed.

No point doing anything to the text if MWE's allowed. The extra's only purpose
is to protect MWE's

Author: Crozzers

lib/markdown2.py

@@ -3160,6 +3160,10 @@ def __init__(self, md: Markdown, options: Union[dict, bool]):
                 , re.S | re.X)
 
     def run(self, text):
+        if self.options['allowed']:
+            # if middle word em is allowed, do nothing. This extra's only use is to prevent them
+            return text
+
         # run strong and whatnot first
         # this also will process all strict ems
         text = super().run(text)