refactor How a Matrix Works doc

Hand Wire guide tidying, part 2

Hand Wire guide tidying

clean up Firmware Setup section in Hand Wire guide

remove collapsible section for Compiling; redirect to Building Firmware doc

replace QMK Toolbox image in Hand Wire guide

Showing a current version of QMK Toolbox

restructure Hand Wire Guide

split Hand Wire Preamble to a separate doc

CSS updates: ul and pre elements

Polish Configurator section

Adjust the H2 and H2 margins

reduce the line-height of the sidebar

rearrange the sidebar a bit

limit the TOC to H1 and H2

remove line drawing chars

make custom_keycode_names.md a faq entry instead

reduce space on h3s

break feature_advanced_keycodes.md up into multiple files

improve our docsify setup

fix numbering