Generate links to definition in source code pages on docs.rs and dev-docs.bevyengine.org (#12965)

# Objective

- Fix issue #2611

## Solution

- Add `--generate-link-to-definition` to all the `rustdoc-args` arrays
in the `Cargo.toml`s (for docs.rs)
- Add `--generate-link-to-definition` to the `RUSTDOCFLAGS` environment
variable in the docs workflow (for dev-docs.bevyengine.org)
- Document all the workspace crates in the docs workflow (needed because
otherwise only the source code of the `bevy` package will be included,
making the argument useless)
- I think this also fixes #3662, since it fixes the bug on
dev-docs.bevyengine.org, while on docs.rs it has been fixed for a while
on their side.

---

## Changelog

- The source code viewer on docs.rs now includes links to the
definitions.

Author: SkiFire13

.github/workflows/docs.yml

@@ -58,8 +58,19 @@ jobs:
       - name: Build docs
         env:
           # needs to be in sync with [package.metadata.docs.rs]
-          RUSTDOCFLAGS:  -Zunstable-options --cfg=docsrs
-        run: cargo doc --all-features --no-deps -p bevy -Zunstable-options -Zrustdoc-scrape-examples
+          RUSTDOCFLAGS: -Zunstable-options --cfg=docsrs --generate-link-to-definition
+        run: cargo doc \
+            -Zunstable-options \
+            -Zrustdoc-scrape-examples \
+            --all-features \
+            --workspace \
+            --no-deps \
+            --exclude ci \
+            --exclude errors \
+            --exclude bevy_mobile_example \
+            --exclude build-wasm-example \
+            --exclude build-templated-pages \
+            --exclude example-showcase
 
       #  This adds the following:
       #   - A top level redirect to the bevy crate documentation

Cargo.toml

@@ -3339,6 +3339,6 @@ lto = "fat"
 panic = "abort"
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true
 cargo-args = ["-Zunstable-options", "-Zrustdoc-scrape-examples"]

crates/bevy_a11y/Cargo.toml

@@ -20,5 +20,5 @@ accesskit = "0.16"
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_animation/Cargo.toml

@@ -42,5 +42,5 @@ uuid = { version = "1.7", features = ["v4"] }
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_app/Cargo.toml

@@ -38,5 +38,5 @@ console_error_panic_hook = "0.1.6"
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_asset/Cargo.toml

@@ -67,5 +67,5 @@ bevy_log = { path = "../bevy_log", version = "0.15.0-dev" }
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_asset/macros/Cargo.toml

@@ -22,5 +22,5 @@ quote = "1.0"
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_audio/Cargo.toml

@@ -52,5 +52,5 @@ android_shared_stdcxx = ["cpal/oboe-shared-stdcxx"]
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_color/Cargo.toml

@@ -28,5 +28,5 @@ serialize = ["serde"]
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true

crates/bevy_core/Cargo.toml

@@ -39,5 +39,5 @@ serde_test = "1.0"
 workspace = true
 
 [package.metadata.docs.rs]
-rustdoc-args = ["-Zunstable-options"]
+rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
 all-features = true