Integrate build and documentation of Ltac2

Since Ltac2 cannot be put under the stdlib logical root (some file names
would clash), we move it to the `user-contrib` directory, to avoid adding
another hardcoded path in `coqinit.ml`, following a suggestion by @ejgallego.

Thanks to @Zimmi48 for the thorough documentation review and the
numerous suggestions.

1 files changed, 12 insertions, 0 deletions

diff --git a/test-suite/ltac2/errors.v b/test-suite/ltac2/errors.v
new file mode 100644
index 0000000000..c677f6af5d
--- /dev/null
+++ b/test-suite/ltac2/errors.v
@@ -0,0 +1,12 @@
+Require Import Ltac2.Ltac2.
+
+Goal True.
+Proof.
+let x := Control.plus
+  (fun () => let _ := constr:(nat -> 0) in 0)
+  (fun e => match e with Not_found => 1 | _ => 2 end) in
+match Int.equal x 2 with
+| true => ()
+| false => Control.throw (Tactic_failure None)
+end.
+Abort.