Fix #302, including their ASCII variants.
- Don't use quotes `'` that are not surrounded by spaces.
- However, notation `'(⊢@{' PROP } )` prevents parsing `(⊢@{PROP} Q)` using the
`⊢@{PROP} Q` notation.

To fix that, we force left-factorization: we add a notation for `'(⊢@{' PROP }
Q )`, defined to coincide with '⊢@{' PROP } Q but which can be left-factored
with `( '⊢@{' PROP } )`.

- Add left and right operator sections for (bi)entailment
- Add tests.

Also do all of the above also for ASCII notations, except for operator sections,
which seem to require more discussion.

add wp proof rule for recursive functions

See merge request iris/iris!425

Lemmas stating that big ops are commuting with op/sep.

See merge request iris/iris!422

Document `%H` pattern.

Closes #305

See merge request iris/iris!423

Fix iIntros on forall

Closes #307

See merge request iris/iris!424

Fixes #307.

ASCII notation

Closes #270

See merge request iris/iris!396

- all ascii notation is marked "only parsing" so this PR shouldn't
  change anything for anyone using only unicode notation.
- the algorithm for creating an ascii notation is pretty simple.
  - \ast -> *
  - \triangleright -> |>
  - \vee -> \/
  - \wedge -> /\
  - \forall -> forall
  - \exists -> exists
  - \ast -> **

make names of more `f_op`/`f_core` rewrite lemmas more consistent

See merge request iris/iris!403

This closes issue #305.

Add support for pure names in intro patterns

Closes #88

See merge request iris/iris!400

Notably this support relies on string to identifier conversion, which
works natively using Ltac2 in Coq 8.11+ and with a plugin
(https://github.com/ppedrot/coq-string-ident) in Coq 8.10. To use it,
you must replace intro_patterns.string_to_ident_hook with a real
implementation; see https://gitlab.mpi-sws.org/iris/string-ident for a
working implementation that works with Coq 8.11 (using Ltac2).

The syntax is %H (within a string intro pattern). This is technically
backwards-incompatible, because this was previously supported and parsed
as % and H separately. To restore the old behavior, separate with a
space, eg [% H].

Add insert delete lemma for big ops over gmap

See merge request iris/iris!420

add pair_included, auth_frag_core, singleton_core_total

See merge request iris/iris!421