module: add :input bidi

* module: add :input bidi

Co-authored-by: Yoav Marco <yoavm448@gmail.com>

* docs(bidi): flesh out README.org

Co-authored-by: Itai Y. Efrat <itai3397@gmail.com>

* feat(bidi): add +bidi-global-mode

* docs(bidi): improve font setting instructions

* feat(bidi): add +bidi-(hebrew|arabic)-font

Since the Hebrew and Arabic unicode blocks cover the vast majority of
RTL languages used today, we provide these fonts so end users don't have
to bother with setting up the hooks themselves.

* feat(bidi): add smart fontify

Adds support for using the bidi fonts on surrounding whitespace and
punctuation through. On by default, customizable through
+bidi-want-smart-fontify and +bidi-smart-fontify-keywords.

Also adds face versions of the bidi fonts.

* docs(bidi): recommend known good nastaliq fonts

* fix(bidi): re-set bidi faces after changing fonts

* feat(bidi): add +bidi-paragraph-direction

This allows users to choose what bidi-paragraph-direction is set to when
+bidi-mode is on, so they can choose if they want per paragraph
alignment (the default) or to force everything to be aligned RTL

* docs(bidi): conform to verbatim/code conventions

* docs(bidi): add font overview to Features

* docs(bidi): warn on rtl forced alignment footgun

+bidi-paragraph-direction is a nice variable to have if you primarily
use +bidi-mode for rtl text buffers, but it shouldn't be used in
conjunction with +bidi-global-mode since it messes up English buffers.

Co-authored-by: Yoav Marco <yoavm448@gmail.com>

docs/modules.org

@@ -89,6 +89,7 @@ Modules that reconfigure or augment packages or features built into Emacs.
 + wanderlust =+gmail= - TODO
 
 * :input
++ [[file:../modules/input/bidi/README.org][bidi]] - (tfel ot) thgir etirw uoy gnipleh
 + [[file:../modules/input/chinese/README.org][chinese]] - TODO
 + [[file:../modules/input/japanese/README.org][japanese]] - TODO
 + [[file:../modules/input/layout/README.org][layout]] =+azerty +bepo= - TODO