Fix pygments style

New theme of docs (Victoria+) respects pygments_style.
Since we starts using Victoria reqs while being on Ussuri,
this patch ensures proper rendering both in Ussuri and Victoria.

Change-Id: Iad418798277b9d7a1190e42e9079080a3d2707f3

Author: fuzihao7

Diff for: doc/source/conf.py

@@ -88,7 +88,7 @@
 # show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = 'native'
 
 # A list of ignored prefixes for module index sorting.
 # modindex_common_prefix = []

Diff for: releasenotes/source/conf.py

@@ -108,7 +108,7 @@
 # show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = 'native'
 
 # A list of ignored prefixes for module index sorting.
 # modindex_common_prefix = []