Merge pull request embassy-rs#3860 from bugadani/docs

Document std/wasm in embassy-time

embassy-time/Cargo.toml

@@ -24,9 +24,6 @@ target = "x86_64-unknown-linux-gnu"
 features = ["defmt", "std"]
 
 [features]
-std = ["tick-hz-1_000_000", "critical-section/std", "dep:embassy-time-queue-utils"]
-wasm = ["dep:wasm-bindgen", "dep:js-sys", "dep:wasm-timer", "tick-hz-1_000_000", "dep:embassy-time-queue-utils"]
-
 ## Display the time since startup next to defmt log messages.
 ## At most 1 `defmt-timestamp-uptime-*` feature can be used.
 ## `defmt-timestamp-uptime` is provided for backwards compatibility (provides the same format as `uptime-us`).
@@ -39,8 +36,18 @@ defmt-timestamp-uptime-ts = ["defmt"]
 defmt-timestamp-uptime-tms = ["defmt"]
 defmt-timestamp-uptime-tus = ["defmt"]
 
+#! ### Time Drivers
+
+#! Usually, time drivers are defined by a HAL, or a companion crate to the HAL. For `std` and WASM
+#! environments, as well as for testing purposes, `embassy-time` provides some default time drivers
+#! that may be suitable for your use case. You can enable one of the following features to use them.
+
 ## Create a `MockDriver` that can be manually advanced for testing purposes.
 mock-driver = ["tick-hz-1_000_000", "dep:embassy-time-queue-utils"]
+## Create a time driver for `std` environments.
+std = ["tick-hz-1_000_000", "critical-section/std", "dep:embassy-time-queue-utils"]
+## Create a time driver for WASM.
+wasm = ["dep:wasm-bindgen", "dep:js-sys", "dep:wasm-timer", "tick-hz-1_000_000", "dep:embassy-time-queue-utils"]
 
 #! ### Generic Queue