tweakdefaults: enable word-diff by default

It's another creature comfort in diff output, we may as well include
it alongside git-diffs and showfunc.

mercurial/ui.py

@@ -71,6 +71,7 b' status.terse = u'
 [diff]
 git = 1
 showfunc = 1
+word-diff = 1
 """
 
 samplehgrcs = {