Add missing types to UniformNode

[shotamatsuda]

This PR adds missing types to UniformNode. They are undocumented but commonly used throughout TSL code in Three.js.

1. Factory function with a type name:

const node = uniform('vec3') // UniformNode<'vec3', Vector3>

2. this as the last parameter of callbacks passed to onUpdate-related functions.

declare const matrix: Matrix4
const node = uniform('vec3').onRenderUpdate(
  (_, { value }) => value.setFromMatrixPosition(matrix)
)

[shotamatsuda]

@Methuselah96 Just to confirm, am I correct that the JSDoc tests are intended to detect suspicious changes and potential incompatibilities made by changes in Three.js, or should I update JSDocs as part of PR?