Use absolute link to PROVIDERS.md

The relative ./PROVIDERS.md link resolves on GitHub but not in the
built docs, where it points at target/doc/rustls/PROVIDERS.md. The
docs workflow's lychee step fails on it, and docs.rs serves a 404.

Link to the file on GitHub instead, and regenerate README.md with
admin/pull-readme. Also fix a "worthyness" typo in PROVIDERS.md.

PROVIDERS.md

@@ -6,7 +6,7 @@ of third-party cryptography providers available for Rustls.
 [README]: https://github.com/rustls/rustls#cryptography-providers
 
 These projects have not been evaluated by the Rustls maintainers, and no claim
-is made to their production worthyness or overall quality.
+is made to their production worthiness or overall quality.
 
 | Repository | Description |
 | -- | -- |

README.md

@@ -115,7 +115,7 @@ See the [Making a custom CryptoProvider] section of the documentation for more i
 on this topic.
 
 [Making a custom CryptoProvider]: https://docs.rs/rustls/latest/rustls/crypto/struct.CryptoProvider.html#making-a-custom-cryptoprovider
-[PROVIDERS.md]: ./PROVIDERS.md
+[PROVIDERS.md]: https://github.com/rustls/rustls/blob/main/PROVIDERS.md
 
 # Example code
 

rustls/src/lib.rs

@@ -78,7 +78,7 @@
 //! on this topic.
 //!
 //! [Making a custom CryptoProvider]: https://docs.rs/rustls/latest/rustls/crypto/struct.CryptoProvider.html#making-a-custom-cryptoprovider
-//! [PROVIDERS.md]: ./PROVIDERS.md
+//! [PROVIDERS.md]: https://github.com/rustls/rustls/blob/main/PROVIDERS.md
 //!
 //! ## Design overview
 //!