Update documentation on no_std support. (#111)

no_std support was removed in 2020 with PR #29. This change updates the documentation to reflect that as suggested in PR #89. It still mentions no_std, which will hopefully keep it on our minds enough to check sometimes and see if the upstream problem has been resolved.

Co-authored-by: Jane Losare-Lusby <[email protected]>

README.md

@@ -171,23 +171,9 @@ avoid using `eyre::Report` as your public error type.
 
 ## No-std support
 
-**NOTE**: tests are currently broken for `no_std` so I cannot guarantee that
-everything works still. I'm waiting for upstream fixes to be merged rather than
-fixing them myself, so bear with me.
-
-In no_std mode, the same API is almost all available and works the same way. To
-depend on Eyre in no_std mode, disable our default enabled "std" feature in
-Cargo.toml. A global allocator is required.
-
-```toml
-[dependencies]
-eyre = { version = "0.6", default-features = false }
-```
-
-Since the `?`-based error conversions would normally rely on the
-`std::error::Error` trait which is only available through std, no_std mode will
-require an explicit `.map_err(Report::msg)` when working with a non-Eyre error
-type inside a function that returns Eyre's error type.
+No-std support was removed in 2020 in [commit 608a16a] due to unaddressed upstream breakages.
+[commit 608a16a]:
+https://github.com/eyre-rs/eyre/pull/29/commits/608a16aa2c2c27eca6c88001cc94c6973c18f1d5
 
 ## Comparison to failure
 

eyre/src/lib.rs

@@ -236,23 +236,9 @@
 //!
 //! ## No-std support
 //!
-//! **NOTE**: tests are currently broken for `no_std` so I cannot guarantee that
-//! everything works still. I'm waiting for upstream fixes to be merged rather than
-//! fixing them myself, so bear with me.
-//!
-//! In no_std mode, almost all the API is available and works the same way. To
-//! depend on Eyre in no_std mode, disable our default enabled "std" feature in
-//! Cargo.toml. A global allocator is required.
-//!
-//! ```toml
-//! [dependencies]
-//! eyre = { version = "0.6", default-features = false }
-//! ```
-//!
-//! Since the `?`-based error conversions would normally rely on the
-//! `std::error::Error` trait which is only available through std, no_std mode will
-//! require an explicit `.map_err(Report::msg)` when working with a non-Eyre error
-//! type inside a function that returns Eyre's error type.
+//! No-std support was removed in 2020 in [commit 608a16a] due to unaddressed upstream breakages.
+//! [commit 608a16a]:
+//! https://github.com/eyre-rs/eyre/pull/29/commits/608a16aa2c2c27eca6c88001cc94c6973c18f1d5
 //!
 //! ## Comparison to failure
 //!