hidden: move hiddenrevs set on the repository
This set is always accessed through the repo for now. Having this set
carried by the changelog make it complicated to:
- initialize it, computing hidden set may involve revset call
- lazy compute it, (1) only the changelog can detect someone access it,
(2) only the repo have enought knowledge to compute it.
In later version I expect he changelog to apply filtering itself and the set to
be carried by changelog again.
$ hg init
$ python -c 'file("a", "wb").write("confuse str.splitlines\nembedded\rnewline\n")'
$ hg ci -Ama -d '1 0'
adding a
$ echo clean diff >> a
$ hg ci -mb -d '2 0'
$ hg diff -r0 -r1
diff -r 107ba6f817b5 -r 310ce7989cdc a
--- a/a Thu Jan 01 00:00:01 1970 +0000
+++ b/a Thu Jan 01 00:00:02 1970 +0000
@@ -1,2 +1,3 @@
confuse str.splitlines
embedded\rnewline (esc)
+clean diff