Update documentation for ImageBitmapLoader options

[jwheare]

Remove grammatical errors and clarified the configuration requirements for image bitmap options and their comparison to regular images.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	355.56 84.51	355.56 84.51	+0 B +0 B
WebGPU	617.29 171.26	617.29 171.26	+0 B +0 B
WebGPU Nodes	615.89 171.01	615.89 171.01	+0 B +0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	487.73 119.38	487.73 119.38	+0 B +0 B
WebGPU	688.74 187.04	688.74 187.04	+0 B +0 B
WebGPU Nodes	638.58 174.23	638.58 174.23	+0 B +0 B

[jwheare]

Actually, hold off merging. This could be clarified further to emphasis that flipY is set to true by default on Texture, so in most cases the option will be needed.

[jwheare]

Ok good to go.