Hide some members from the public docs.

[rodrigogiraoserrao]

See relevant issue: #3076.
Some methods need to be implemented to make the widget work but the user doesn't really care about them. For that matter, we can hide them from the public documentation.

I decided to hide these methods that some widgets inherit and document:

• "compose"
• "render"
• "render_line"
• "render_lines"
• "get_content_width"
• "get_content_height"
• "on_mount"

On a case-by-case basis, we may also want to hide specific methods from specific widgets, but that probably entails manually curating such a list of excluded methods.

[willmcgugan]

That looks right. Although for the case of on_mount and other handlers, we can make those private with an underscore. Textual will still call those handlers, and don't need to worry about excluding them.

[rodrigogiraoserrao]

[...] for the case of on_mount [...] we can make those private with an underscore.

Of course. Updated.