Added design doc for Material 3 ColorScheme. (#6416)

Author: darrenaustin

firebase.json

@@ -124,6 +124,7 @@
       { "source": "/go/center-floating-label-inputdecoration", "destination": "https://docs.google.com/document/d/1sxP91vZiY7McmSMmzrboklIJWQ_6pSS9MBSCrQq016M/edit#", "type": 301 },
       { "source": "/go/change-default-textselectionhandlecolor-to-accentcolor", "destination": "https://docs.google.com/document/d/1RJQd5ABWJ_7DZN19aTZBCE7xHzlC4MYBP1bWE2FWcvc/edit", "type": 301 },
       { "source": "/go/clip-behavior", "destination": "https://docs.google.com/document/d/1gC5Di4ykTCqupD77PWpy9D8xXo0Ide5CnrH0zzVIhKo/edit", "type": 301 },
+      { "source": "/go/colorscheme-m3", "destination": "https://docs.google.com/document/d/1mY1ahBQEMAfsawGJMX5S34pXb7c8dHGatyotClReeas/edit#heading=h.cnnhzna3pz6d", "type": 301 },
       { "source": "/go/cupertino-context-menu-action", "destination": "https://docs.google.com/document/d/1lCuPyAbIzAr0c2KIEZhREC_EnkTKBxNiqP6lGLT-KpU/edit", "type": 301 },
       { "source": "/go/cupertino-increase-contrast", "destination": "https://docs.google.com/document/d/1kePVlqWvJu5Ph0RL6wgg67F3SATmsJ8QY5N0S1MvaGg/edit#", "type": 301 },
       { "source": "/go/cupertino-switch-onoff-labels", "destination": "https://docs.google.com/document/d/1DD5gx8x0ej5AJzGxzpr4hpgpqsvcDu-ozKliGnhHm7c/edit#", "type": 301 },
@@ -349,11 +350,11 @@
       { "source": "/youtube", "destination": "https://youtube.com/flutterdev", "type": 301 }
     ],
     "headers": [
-      { 
-        "source": "/f/*.json", 
+      {
+        "source": "/f/*.json",
         "headers": [
           {"key": "Access-Control-Allow-Origin", "value": "*"}
-        ] 
+        ]
       },
       {
         "source": "**/*.@(jpg|jpeg|gif|png)",