do not parse `|` as infix in patterns; parse `|}` as `|` `}`

* use mixfix `(p1 | … | pn)` notation for nested disjunctive patterns,
rather than infix `|`, making pattern syntax consistent with term
syntax.
* disable extending `pattern` grammar with notation incompatible with
the nested disjunctive pattern syntax `(p1 | … | pn)`, such as the `(p
| q)` divisibility notation used by `Numbers`.
* emit a (disabled by default) `disj-pattern-notation` warning when such
`Notation` is attempted.
* update documentation accordingly; document incompatibilities in
`changelog`.
* comment special treatment of `(num)` in grammar.
* update file extensions in `Pcoq` header comment.
* correct the keyword declarations to reflect the contents of the
grammar files; perhaps there should be an option to disable implicit
keyword extension in a `.mlg` file, so that these lists could actually
be checked.
* parse the `|}` manifest record terminator as `|` followed by `}`,
eliminating the `|}` token which conflicts with notations that use `|`
as a terminator (such as, absolute value, norm, or cardinal in
MathComp). Since `|` is now an `operconstr` _and_ `pattern` terminator,
`bar_cbrace` rule checks for contiguous symbols, this change entails no
visible behaviour change.

1 files changed, 2 insertions, 0 deletions

diff --git a/parsing/pcoq.ml b/parsing/pcoq.ml
index a78ad4f842..b474c8e9a9 100644
--- a/parsing/pcoq.ml
+++ b/parsing/pcoq.ml
@@ -411,6 +411,8 @@ module Prim =
     let ne_string = Entry.create "Prim.ne_string"
     let ne_lstring = Entry.create "Prim.ne_lstring"
 
+    let bar_cbrace = Entry.create "'|}'"
+
   end
 
 module Constr =