fix point repr & shader

CHANGELOG.md

src/mol-geo/geometry/points/points.ts

src/mol-gl/_spec/renderer.spec.ts

src/mol-gl/renderable/points.ts

src/mol-gl/renderer.ts

src/mol-gl/shader/points.frag.ts

src/mol-repr/structure/representation/point.ts

src/mol-repr/structure/visual/element-point.ts