docs: Add matrix room links (#141)

src/introduction.md

@@ -8,9 +8,12 @@ Rust support for these devices is still a work in progress, and progress is bein
 
 For tools and libraries relating to Rust on ESP, please see the [esp-rs organization][esp-rs] on GitHub. This organization is managed by employees of Espressif as well as members of the community.
 
+Feel free to join the [`esp-rs` community on Matrix][matrix] for all technical questions and issues! The community is open to everyone.
+
 [rust]: https://www.rust-lang.org/
 [espressif]: https://espressif.com/
 [esp-rs]: https://github.com/esp-rs/
+[matrix]: https://matrix.to/#/#esp-rs:matrix.org
 
 ## Who This Book Is For
 

src/troubleshooting/index.md

@@ -1,6 +1,8 @@
 # Troubleshooting
 
-This chapter lists certain questions and common problems we have encountered over the time, along with their solutions. This page collects common issues independent of the chosen ESP ecosystem.
+This chapter lists certain questions and common problems we have encountered over time, along with their solutions. This page collects common issues independent of the chosen ESP ecosystem. If you can't find your issue listed here, feel free to open an issue in the appropriate repository or ask on our [Matrix room][matrix].
+
+[matrix]: https://matrix.to/#/#esp-rs:matrix.org
 
 ## Using the Wrong Rust Toolchain