- tkc1800.h
  - updated to use #pragma once
  - visual alignment
- update config.h files to use #pragma once
- update all keymaps to use #include QMK_KEYBOARD_H
- delete redundant mod mask, KC_TRNS, and KC_NO definitions
- reformat keymap layers for readability
- add block comment for Function layer in default keymap
- delete commented action_get_macro code blocks (deprecated function)
- update files to better conform with QMK coding conventions
- update smt keymap to use set_single_persistent_default_layer (instead of persistent_default_layer_set)
- replace instances of `?=` with `=` in rules.mk

- correct key sizes and positioning
- reformat file so each physical key object has its own line for readability
- update and add `label` keys for readability

- fix image gallery link
- update Hardware Supported and Hardware Availability lines
- update make example (add :default suffix)
- update QMK Docs links (Newbs Guide; grammar)