PERF: Skip checking prefixes after one is found to be valid

This commit is a follow-up of d4ff3ad (added multiple files and
prefix checks)

Author: jcfr

codespell.py

@@ -120,15 +120,15 @@ def spell_check_file(filename, spell_checker, mime_type="", output_lvl=1, prefix
                 if error.word.startswith(pre):
                     # check if the word is only the prefix
                     if len(pre) == len(error.word):
-                        continue
+                        break
 
                     # remove the prefix
                     wrd = error.word[len(pre) :]
                     if output_lvl > 1:
                         print("Trying without prefix: ", error.word, wrd)
                     try:
                         if spell_checker.check(wrd):
-                            continue
+                            break
                     except BaseException:
                         print("Caught an exception for word", error.word, wrd)