- Separated out the simpler invocations of tactics from their full
  forms. In the process we now document what parts of a tactic are
  optional.
- Convey what the common and rare tactics are, for example that the
  argument to `iModIntro` is rarely needed.
- Use "destruct" to talk about invoking an intro pattern, rather than
  eliminate, to stay closer to Coq terminology and avoid this potentially
  confusing PL term.
- Added an overview of the "grammar entries" relevant to many tactics
  (ipat, selpat, spat, and pm_trm). Added links to those sections
  everywhere.

make pure_exec_fill not an instance any more

See merge request iris/iris!588

bupd, fupd: add idempotence lemmas

See merge request iris/iris!592

Add back a proofmode test for issue #288

See merge request iris/iris!584

Use original pattern in iDestruct error messages

See merge request iris/iris!550

This test is incompatible with Coq 8.8 and Coq 8.9, but Iris no longer
supports those versions.

multi-package repositories

See merge request iris/iris!514

add big_opM_singletons

See merge request iris/iris!567

avoid (e)apply in wp_expr_eval

See merge request iris/iris!582

Rename mapsto_mapsto_ne and add easier-to-use variant

See merge request iris/iris!574

provide _big variant of gen_heap_init

Closes #361

See merge request iris/iris!580

Documentation on Iris equalities (take 2)

See merge request iris/iris!575