diff: don't show function name by default
We'd mistakenly made the -p option always on, which meant there was no
way to turn it off. It also meant that we were sometimes splitting
multibyte characters in function name, which isn't a good default.
% init
% commit
adding base
% qnew mqbase
% qrefresh
% qdiff
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@
-base
+patched
% qdiff dirname
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@
-base
+patched