notmuch: Update to 0.32

Changelog:
Notmuch 0.32 (2021-05-02)
=========================

General
-------

This release includes a significant overhaul of the configuration
management facilities for notmuch.  The previous distinction between
configuration items that can be modified via plain text configuration
files and those that must be set in the database via the "notmuch
config" subcommand is gone, and all configuration items can be set in
both ways.  The external configuration file overrides configuration
items in the database. The location of database, hooks, and
configuration files is now more flexible, with several new
configuration variables. In particular XDG locations are now supported
as fallbacks for database, configuration and hooks. For more
information see `notmuch-config(1)`.

Library
-------

To support the new configuration facilities, several functions and
constants have been added to the notmuch API. Most notably:

- `notmuch_database_create_with_config`
- `notmuch_database_open_with_config`
- `notmuch_database_load_config`
- `notmuch_config_get`

A previously requested API change is that `notmuch_database_reopen` is
now exposed (and generalized).

The previously severe slowdowns from large numbers calls to
notmuch_database_remove_message or notmuch_message_delete in one
session has been fixed.

As always, the canonical source of API documentation is
`lib/notmuch.h`, or the doxygen formatted documentation in `notmuch(3)`

CLI
---

The `notmuch config set` subcommand gained a `--database` argument to
specify that the database should be updated, rather than a config file.

The speed of `notmuch new` and `notmuch reindex` in dealing with large
numbers of mail file deletions is significantly improved.

Emacs
-----

Completion related updates include: de-duplicating tags offered for
completion, use the actual initial input in address completion, allow
users to opt out of notmuch address completion, and do not force Ido
when prompting for senders.

Some keymaps used to contain bindings for unnamed commands.  These
lambda expressions have been replaced by named commands (symbols), to
ease customization.

Lexical binding is now used in all notmuch-emacs libraries.

Fix bug in calling `notmuch-mua-mail` with a non-nil RETURN-ACTION.

Removed, inlined or renamed functions and variables:
    `notmuch-address-locate-command`,
    `notmuch-documentation-first-line`, `notmuch-folder`,
    `notmuch-hello-trim', `notmuch-hello-versions` => `notmuch-version`,
    `notmuch-remove-if-not`, `notmuch-search-disjunctive-regexp`,
    `notmuch-sexp-eof`, `notmuch-split-content-type`, and
    `notmuch-tree-button-activate`.


(ryoon)