docs: Don't enable nightly feature for docs.rs

Author: epage

Cargo.toml

@@ -104,7 +104,7 @@ rust-version.workspace = true
 include.workspace = true
 
 [package.metadata.docs.rs]
-all-features = true
+features = ["unstable-doc"]
 rustdoc-args = ["--generate-link-to-definition"]
 
 [package.metadata.release]
@@ -120,6 +120,7 @@ pre-release-replacements = [
 default = ["color"]
 nightly = []
 color = ["dep:anstyle", "dep:anstream"]
+unstable-doc = ["default"]
 
 [dependencies]
 anstyle = { version = "1.0.0", optional = true }