move 麦田 boards into /mt (#16095)

Co-authored-by: Nick Brassel <nick@tzarc.org>

keyboards/mt/blocked65/readme.md

@@ -8,6 +8,6 @@ A 65% PCB sold via TaoBao, commonly sold as part of the Canoe clone referred to
 
 Make example for this keyboard (after setting up your build environment):
 
-    make wheatfield/blocked65:default
+    make mt/blocked65:default
 
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).

keyboards/mt/mt40/readme.md

@@ -10,10 +10,10 @@ A 40% Ortholinear Keyboard
 
 Make example for this keyboard (after setting up your build environment):
 
-    make mt40:default
+    make mt/mt40:default
 
 Flashing example for this keyboard ([after setting up the bootloadHID flashing environment](https://docs.qmk.fm/#/flashing_bootloadhid))
 
-    make mt40:default:flash
+    make mt/mt40:default:flash
 
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).

keyboards/mt/mt64rgb/readme.md

@@ -11,6 +11,6 @@ It supports an ANSI-based 64-key layout, with hotswap sockets and per-key RGB ba
 
 Make example for this keyboard (after setting up your build environment):
 
-    make mt64rgb:default
+    make mt/mt64rgb:default
 
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).

keyboards/mt/mt84/readme.md

@@ -12,11 +12,11 @@ It supports standard 84-key layout, with hotswap sockets and per-key RGB backlig
 
 Make example for this keyboard (after setting up your build environment):
 
-    make mt84:default
+    make mt/mt84:default
     
 Flashing example for this keyboard:
 
-    make mt84:default:flash
+    make mt/mt84:default:flash
 
 To put the board into bootloader mode, either press the reset button on the bottom the PCB or hold Space+B while plugging it in.
 

keyboards/mt/mt980/readme.md

@@ -8,7 +8,7 @@ Hardware Availability: Taobao store https://shop110310565.taobao.com
 
 Make example for this keyboard (after setting up your build environment):
 
-    make mt980:default
+    make mt/mt980:default
 
 See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
 

keyboards/mt/split75/readme.md

@@ -13,11 +13,11 @@ Original work performed by Michael L. Walker, all credit goes to him. I've tidie
 
 Make example for this keyboard (after setting up your build environment):
 
-    make wheatfield/split75:default
+    make mt/split75:default
 
 Flashing example for this keyboard ([after setting up the bootloadHID flashing environment](https://docs.qmk.fm/#/flashing_bootloadhid))
 
-    make wheatfield/split75:default:flash
+    make mt/split75:default:flash
 
 or