stm32,nrf: add warning on docs.rs directing the user to docs.embassy.dev.

embassy-nrf/Cargo.toml

@@ -17,6 +17,7 @@ flavors = [
 
 [package.metadata.docs.rs]
 features = ["nrf52840", "time", "defmt", "unstable-pac", "gpiote", "time-driver-rtc1"]
+rustdoc-args = ["--cfg", "docsrs"]
 
 [features]
 default = ["rt"]

embassy-nrf/src/lib.rs

@@ -1,5 +1,9 @@
 #![no_std]
 #![allow(async_fn_in_trait)]
+#![cfg_attr(
+    docsrs,
+    doc = "<div style='padding:30px;background:#810;color:#fff;text-align:center;'><p>You might want to <a href='https://docs.embassy.dev/embassy-nrf'>browse the `embassy-nrf` documentation on the Embassy website</a> instead.</p><p>The documentation here on `docs.rs` is built for a single chip only (nRF52840 in particular), while on the Embassy website you can pick your exact chip from the top menu. Available peripherals and their APIs change depending on the chip.</p></div>\n\n"
+)]
 #![doc = include_str!("../README.md")]
 #![warn(missing_docs)]