futures: readme, docs improvements.

embassy-futures/README.md

@@ -1,10 +1,28 @@
 # embassy-futures
 
-Utilities for working with futures:
+An [Embassy](https://embassy.dev) project.
+
+Utilities for working with futures, compatible with `no_std` and not using `alloc`. Optimized for code size,
+ideal for embedded systems.
+
+- Future combinators, like [`join`](join) and [`select`](select)
+- Utilities to use `async` without a fully fledged executor: [`block_on`](block_on::block_on) and [`yield_now`](yield_now::yield_now).
+
+## Interoperability
+
+Futures from this crate can run on any executor.
+
+## Minimum supported Rust version (MSRV)
+
+Embassy is guaranteed to compile on the latest stable Rust version at the time of release. It might compile with older versions but that may change in any new patch release.
+
+## License
+
+This work is licensed under either of
+
+- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
+  <http://www.apache.org/licenses/LICENSE-2.0>)
+- MIT license ([LICENSE-MIT](LICENSE-MIT) or <http://opensource.org/licenses/MIT>)
+
+at your option.
 
-- [`select`](select::select) - waiting for one out of two futures to complete.
-- [`select3`](select::select3) - waiting for one out of three futures to complete.
-- [`select4`](select::select4) - waiting for one out of four futures to complete.
-- [`select_array`](select::select_array) - waiting for one future in an array of futures to complete.
-- [`select_slice`](select::select_slice) - waiting for one future in a slice of futures to complete.
-- [`yield_now`](yield_now::yield_now) - yielding the current task.