tests/test-diff-change.out

status: add the --change option to display files changed in a revision

This option is similar to the one already used for the diff command.
Unfortunately, the c and C short option are already used for status, so there
is no corresponding short option. However, there is no short option for --rev
either, so that's consistent.

invoking hg diff --nodates --change 1:
diff -r 4bb65dda5db4 -r e9b286083166 file.txt
--- a/file.txt
+++ b/file.txt
@@ -1,1 +1,1 @@
-first
+second

invoking hg diff --nodates --change e9b286083166:
diff -r 4bb65dda5db4 -r e9b286083166 file.txt
--- a/file.txt
+++ b/file.txt
@@ -1,1 +1,1 @@
-first
+second

invoking hg diff --nodates --change 6:
diff -r e8a0797e73a6 -r aa9873050139 file.txt
--- a/file.txt
+++ b/file.txt
@@ -6,6 +6,6 @@
 5
 6
 7
-8
+y
 9
 10

EOF