* neomutt: support list in binds.map
Closes#1245
Adds support for specifying programs.neomutt.binds[].map as a list. If
specified as a list, then the binds will be concatenated with a ",".
* neomutt: add deprecation warning for (binds|macros).map as string
Added note that specifying 'programs.neomutt.(binds|macros).map' as a string is deprecated. Instead, use the list form.
* neomutt: note deprecation warning in release notes
Added note that specifying 'programs.neomutt.(binds|macros).map' as a
single string is deprecated in favor of specifying it as a list
* neomutt: add assertion that map is not empty
Added an assertion that each 'programs.neomutt.(binds|macros).map' list contains at least one element.
* neomutt: Fix eval error when primary account not enabled
If neomutt is enabled for an account, but not the primary account, the
configuration will fail with "list index 0 is out of bounds".
This adds the first neomutt-enabled account as a fallback.
* neomutt: add regression test/update tests
The `accounts.email.accounts.<name>.neomutt.extraConfig` option is
included twice in the resulting config file for the account. One time as
part of the `mraSection`, one time as part of `accountStr` (`accountStr`
includes the `mraSection`). This removes that duplication. I opted to
keep the one in `accounStr`, since `extraConfig` doesn't necessarily
have anything to do with the `mraSection`.
