ApproxEq trait + refactorings

[Bromeon]

Changes:

Add ApproxEq trait and implement it for many builtin types.

• This standardizes checking for approximate equality across types.
• Gets rid of the boilerplate 3rd argument assert_eq_approx!(a, b, is_equal_approx).
  • That argument can still be specified if desired, using assert_eq_approx!(a, b, fn = is_equal_approx).
  • In 95% of cases, it's not needed though.

Refactor modules

• godot::builtin::math is now a public module, which contains:
  • Godot ported functions such as lerp, sign
  • ApproxEq trait + assert_eq_approx!, assert_ne_approx! macros
  • glam utilities: IVec4, GlamConv, etc (internal)
• The above symbols are no longer in godot::builtin. If this turns out to be an issue, we can also revert this in the future; but it might help some discoverability. Some symbols could also be considered to be part of the prelude.
• Move godot::native_structure -> godot::engine::native
  • Added in Implement virtual methods that accept or return pointers (per #191) #272
  • Native structures are now less prominent because rarely used.
• Move real-related symbols into their own real.rs file (internal; API unaffected).

Refactor import statements (just around geometric types, not whole codebase)

• Remove wildcard imports
• Remove nested import statements
• Consistent order

[GodotRust]

API docs are being generated and will be shortly available at: https://godot-rust.github.io/docs/gdext/pr-314

[Bromeon]

bors r+

[bors]

Build succeeded!

The publicly hosted instance of bors-ng is deprecated and will go away soon.

If you want to self-host your own instance, instructions are here.
For more help, visit the forum.

If you want to switch to GitHub's built-in merge queue, visit their help page.

• full-ci