update symbol-avoid-edges doc copy to acknowledge the existence of gl…

…obal collision detection (mapbox#9157)

src/style-spec/reference/v8.json

@@ -1006,7 +1006,7 @@
     "symbol-avoid-edges": {
       "type": "boolean",
       "default": false,
-      "doc": "If true, the symbols will not cross tile edges to avoid mutual collisions. Recommended in layers that don't have enough padding in the vector tile to prevent collisions, or if it is a point symbol layer placed after a line symbol layer.",
+      "doc": "If true, the symbols will not cross tile edges to avoid mutual collisions. Recommended in layers that don't have enough padding in the vector tile to prevent collisions, or if it is a point symbol layer placed after a line symbol layer. When using a client that supports global collision detection, like Mapbox GL JS version 0.42.0 or greater, enabling this property is not needed to prevent clipped labels at tile boundaries.",
       "sdk-support": {
         "basic functionality": {
           "js": "0.10.0",