The "Developing in C++" section name is ambiguous/confusing

[RiverMesa]

This came up on the Godot Discord server the other day.

Basically, it's not immediately clear that the section refers to extending the engine itself (with C++), as opposed to using C++ for scripting (which is a separate matter), so I think it'd be appropriate to alter the name to more accurately represent what the section is meant to cover.

[mhilbrunner]

Most agreed upon new name was Engine development with C++ or just Engine development

[NathanLovato]

Fixed!