More complete linking of API methods in Gallery Examples

[MatthewFlamm]

Describe what maintenance you would like added.

The gallery examples are extremely useful to help users get started. But, often I want to jump from the example to the detailed documentation for the particular method that is used in the example. An example of a gallery example that does this well is https://docs.pyvista.org/version/stable/examples/01-filter/clipping.html, where links to clip, clip_box and so on are provided. An example of a gallery example that does not currently do this well is https://docs.pyvista.org/version/stable/examples/01-filter/project-plane.html where there is no link to project_points_to_plane.

Links to source code.

Example that links to detailed documentation:
https://github.com/pyvista/pyvista/blob/v0.42.3/examples/01-filter/clipping.py

Example that doesn't link to detailed documentation:
https://github.com/pyvista/pyvista/blob/v0.42.3/examples/01-filter/project-plane.py

Pseudocode or Screenshots

No response