Fix simple typo: unconvential -> unconventional

Author: timgates42

prompt_toolkit/styles/.base.py.swp

@@ -83,7 +83,7 @@
 
 
 # People don't use the same ANSI color names everywhere. In prompt_toolkit 1.0
-# we used some unconvential names (which were contributed like that to
+# we used some unconventional names (which were contributed like that to
 # Pygments). This is fixed now, but we still support the old names.
 
 # The table below maps the old aliases to the current names.