rust-config: add support for default config items
Now that configitems.toml exists, we can read from it the default values for
all core config items.
We will add the devel-warning for use of undeclared config items in a later
patch when we're done adding the missing entries for `rhg`.
https://bz.mercurial-scm.org/842
$ hg init repo
$ cd repo
$ echo foo > a
$ hg ci -Ama
adding a
$ hg up -r0000
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo bar > a
Should issue new head warning:
$ hg ci -Amb
adding a
created new head
$ hg up -r0000
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo stuffy > a
Should not issue new head warning:
$ hg ci -q -Amc
$ hg up -r0000
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo crap > a
$ hg branch testing
marked working directory as branch testing
(branches are permanent and global, did you want a bookmark?)
Should not issue warning:
$ hg ci -q -Amd