Fix clouds3d: same JS-comment-in-FRAG_SRC bug as before

Multi-line '//' comment left outside any string in the FRAG_SRC
array. Wrap in single quotes (and stop making this mistake).

vendor/clouds3d.js

@@ -202,8 +202,7 @@ var FRAG_SRC = [
         '// Horizon: cast the ray onto the ground plane (y=0) and sample the satellite image at that world (x,z) coordinate. As the camera drifts forward over time the texture scrolls past, giving the illusion of flying over real terrain. Distant ground fades toward sky colour (atmospheric perspective).
         'float tGround = (ro.y > 0.0 && rd.y < -0.001) ? -ro.y / rd.y : -1.0;',
         'vec3 hitPoint = ro + rd * tGround;',
-        // UV from world (hitPoint - centre) / size + 0.5 — the
-        // mosaic moves with the camera so the centre is always at 0.5
+        '// UV from world (hitPoint - centre) / size + 0.5 — the mosaic moves with the camera so the centre is always at 0.5',
         'vec2 gUv = vec2(hitPoint.x, hitPoint.z);',
         'gUv = (gUv - uGroundCenter) / uGroundSize + 0.5;',
         'vec3 groundCol = texture2D(uGround, gUv).rgb;',