Styles demo commit

The diff in this commit contains sections with all of the following semantics:

minus-style (old line 1)
plus-style (new line 1)
zero-style (line 2)
minus-non-emph-style (old line 4, and unchanged sections of old line 3)
minus-emph-style (deleted word "chaffinch" in old line 3)
plus-non-emph-style (new line 3, and unchanged sections of new line 4)
plus-emph-style (added word "dodo" of new line 4)

Author: dandavison

etc/examples/styles.py

@@ -1,4 +1,4 @@
-# albatross albatross albatross albatross
+# avocet avocet avocet avocet
 # bee-eater bee-eater bee-eater bee-eater
-# chaffinch chaffinch chaffinch chaffinch
-# dodo dodo dodo dodo
+# chaffinch chaffinch chaffinch
+# dodo dodo dodo dodo dodo