Remove requirement for sphinxcontrib-ansi

doc/conf.py

@@ -303,9 +303,3 @@ intersphinx_mapping = dict(
 
 def setup(app):
   pass
-
-# If True, ANSI colour sequences in program output are interpreted. To use this
-# feature, the extension sphinxcontrib.ansi must be enabled and configured. If
-# missing or False, these sequences are not interpreted, but appear in
-# documentation unchanged.
-programoutput_use_ansi = True