docs(awareness): state the range ring's measured ~50 m accuracy

The ring is up to about 49 m off the geodesic radius at 45 degrees, not
a few metres. Also attach the range ring style's JSDoc to its constant.

src/layers/awareness/policy.js

@@ -50,7 +50,6 @@ export const CONTEXT_RIM_HEIGHT_M = 2500;
  *  luminance contrast on light and dark ground alike, and luminance is what
  *  the monochrome styles keep. The core is the Context panel's blue; the halo
  *  is the map-card ink. Widths are screen pixels; `outlineWidth` is per side. */
-
 export const AWARENESS_RANGE_RING_STYLE = Object.freeze({
   color: 'rgba(98, 181, 255, 0.95)',
   outlineColor: 'rgba(4, 12, 16, 0.8)',

src/layers/awareness/rendering.js

@@ -21,7 +21,7 @@ import { formatAwarenessDirection } from './presentation.js';
  * A closed ring of positions `radiusM` along the surface from `groundCenter`,
  * raised to `heightM`. Each bearing steps over a sphere with the ellipsoid's
  * radius of curvature in that direction (Euler's formula), which keeps the
- * ring within a few metres of the true geodesic radius at 250 km.
+ * ring within ~50 m of the true geodesic radius at 250 km.
  * @param {Cesium.Cartesian3} groundCenter Ring centre on the ellipsoid.
  * @param {number} radiusM Surface radius in metres.
  * @param {number} heightM Height of the ring above the ellipsoid.