Resolve doc warning with global enums

If you run `cargo doc`, as apposed to `cargo doc -p godot --no-libs` as
in the CI, you get hit with a warning "warning: redundant explicit link
target" on the docs in this commit.  I'm not sure why these options
together supress the warning (neither individually does).  But this
reduces noise in developer consoles.

godot-core/src/global/mod.rs

@@ -16,8 +16,8 @@
 //!
 //! - Color: [`ColorChannelOrder`][crate::builtin::ColorChannelOrder]
 //! - Projection: [`ProjectionEye`][crate::builtin::ProjectionEye], [`ProjectionPlane`][crate::builtin::ProjectionPlane]
-//! - Rectangle: [`Side`][crate::builtin::Side], [`Corner`][crate::builtin::Corner] <sub>(godot-generated)</sub>
-//! - Rotation: [`EulerOrder`][crate::builtin::EulerOrder] <sub>(godot-generated)</sub>
+//! - Rectangle: [`Side`], [`Corner`] <sub>(godot-generated)</sub>
+//! - Rotation: [`EulerOrder`] <sub>(godot-generated)</sub>
 //! - Variant: [`VariantType`][crate::builtin::VariantType], [`VariantOperator`][crate::builtin::VariantOperator]
 //! - Vector: [`Vector2Axis`][crate::builtin::Vector2Axis], [`Vector3Axis`][crate::builtin::Vector3Axis], [`Vector4Axis`][crate::builtin::Vector4Axis]
 //!