cmdutil: changeset_printer: use methods of filectx/changectx.
This allows extensions that modify changeset metadata (e.g.
description) by overriding methods of changectx to get consistent
behavior from all log-like commands, regardless of whether templates
or styles are used. Without this, overriding changectx methods works
if you use styles or templates, but not with default log format.
This meant adding filectx.extra() for consistency with changectx.
adding a
% default context
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -2,7 +2,7 @@
c
a
a
-b
+dd
a
a
c
% invalid --unified
abort: diff context lines count must be an integer, not 'foo'
% --unified=2
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -3,5 +3,5 @@
a
a
-b
+dd
a
a
% diff.unified=2
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -3,5 +3,5 @@
a
a
-b
+dd
a
a
% diff.unified=2 --unified=1
diff -r cf9f4ba66af2 a
--- a/a
+++ b/a
@@ -4,3 +4,3 @@
a
-b
+dd
a
% invalid diff.unified
abort: diff context lines count must be an integer, not 'foo'
% test off-by-one error with diff -p
adding a
diff -r cb9a9f314b8b a
--- a/a
+++ b/a
@@ -1,0 +1,1 @@
+b
@@ -2,0 +3,1 @@ a
+c