Disable wgpu-core documentation as a workaround for gfx-rs#4905.

This enables `cargo doc` to succeed in a reasonable amount of time,
as long as the reader isn't looking for documentation for `wgpu-core`
itself.

wgpu-core/Cargo.toml

@@ -85,6 +85,12 @@ fragile-send-sync-non-atomic-wasm = [
     "wgt/fragile-send-sync-non-atomic-wasm",
 ]
 
+## Enable full documentation.
+## If this feature is not enabled, some items will be undocumented.
+## This feature is a workaround for <https://github.com/rust-lang/rust/issues/114891>
+## to enable projects which do not need `wgpu-core` documentation to still use `cargo doc`.
+wgpu-core-doc = []
+
 #! ### Backends, passed through to wgpu-hal
 # --------------------------------------------------------------------
 

wgpu-core/src/lib.rs

@@ -2,6 +2,18 @@
 //! It is designed for integration into browsers, as well as wrapping
 //! into other language-specific user-friendly libraries.
 //!
+#![cfg_attr(
+    not(any(not(doc), feature = "wgpu-core-doc")),
+    doc = "\
+## Documentation hidden
+
+As a workaround for [an issue in rustdoc](https://github.com/rust-lang/rust/issues/114891),
+the documentation for `wgpu-core` is empty unless built with
+`cargo doc --features wgpu-core-doc`, which may take a very long time.
+"
+)]
+#![cfg(any(not(doc), feature = "wgpu-core-doc"))]
+//!
 //! ## Feature flags
 #![doc = document_features::document_features!()]
 //!