Enable all-features on docs.rs

Author: taiki-e

futures-util/Cargo.toml

@@ -47,3 +47,6 @@ futures-preview = { path = "../futures", version = "=0.3.0-alpha.16", features =
 futures-executor-preview = { path = "../futures-executor", version = "=0.3.0-alpha.16" }
 futures-test-preview = { path = "../futures-test", version = "=0.3.0-alpha.16" }
 tokio = "0.1.11"
+
+[package.metadata.docs.rs]
+all-features = true

futures/Cargo.toml

@@ -45,3 +45,6 @@ io-compat = ["compat", "futures-util-preview/io-compat"]
 cfg-target-has-atomic = ["futures-core-preview/cfg-target-has-atomic", "futures-util-preview/cfg-target-has-atomic"]
 never-type = ["futures-util-preview/never-type"]
 alloc = ["futures-core-preview/alloc", "futures-sink-preview/alloc", "futures-util-preview/alloc"]
+
+[package.metadata.docs.rs]
+all-features = true