* add matrix_diagram.md
* refactor default and via keymaps
- use four-space indent
- grid-align keycodes
* info.json: apply friendly formatting
* standardize default and via keymaps
Place the `KC_NUHS` and `KC_NUBS` keycodes on the correct keys.
* add LAYOUT_ansi with reference keymap
* add LAYOUT_ansi_split_bs with reference keymap
* add LAYOUT_iso with reference keymap
* add LAYOUT_iso_split_bs with reference keymap
