60% Arrow|64-key Tsangan bottom row

[dunk2k]

Description

This PR does not add a keyboard.

Add hybrid bottom row variant for 60% Arrow and 60% 64 key (physical) layouts:

┌──────────────────Tsangan──────────────────┐
┌─────┬───┬─────┬───────────────────────────┬───┬───┬───┬───┐
│1.5u │1u │1.5u │7u                         │1u │1u │1u │1u │
└─────┴───┴─────┴───────────────────────────┴───┴───┴───┴───┘
                                            └────Arrows─────┘

combines the left modifiers and spacebar of Tsangan bottom row with the latter 4x1u keys of 60% Arrow/64-key bottom row.

60% keyboards with both Tsangan bottom row and Arrows bottom row are in scope.

QMK Pull Request

n/a

Checklist

• The VIA support for this keyboard is MERGED in QMK master already (MANDATORY)
• The VIA definition follows the guide here: https://caniusevia.com/docs/layouts
• I have a V3 JSON version for this keyboard definition.(MANDATORY)
• I have tested this keyboard definition using VIA's "Design" tab.
• I have tested this keyboard definition with firmware on a device.
• I have assigned alpha keys and modifier keys with the correct colors.
• The Vendor ID is not 0xFEED

[dunk2k]

Superseded by more than one "Revamp [keyboard name]" PR