Add links to the Rust advanced testing workshop (#2029)

Following up on https://github.com/google/googletest-rust/issues/376

---------

Co-authored-by: Martin Geisler <martin@geisler.net>

src/android/testing/googletest.md

@@ -38,7 +38,12 @@ Error: See failure output above
 - The `use googletest::prelude::*;` line imports a number of
   [commonly used macros and types][prelude].
 
-- This just scratches the surface, there are many builtin matchers.
+- This just scratches the surface, there are many builtin matchers. Consider
+  going through the first chapter of
+  ["Advanced testing for Rust applications"](https://github.com/mainmatter/rust-advanced-testing-workshop),
+  a self-guided Rust course: it provides a guided introduction to the library,
+  with exercises to help you get comfortable with `googletest` macros, its
+  matchers and its overall philosophy.
 
 - A particularly nice feature is that mismatches in multi-line strings are shown
   as a diff:

src/other-resources.md

@@ -47,6 +47,10 @@ A small selection of other guides and tutorial for Rust:
   a series of small presentations covering both basic and advanced part of the
   Rust language. Other topics such as WebAssembly, and async/await are also
   covered.
+- [Advanced testing for Rust applications](https://github.com/mainmatter/rust-advanced-testing-workshop):
+  a self-paced workshop that goes beyond Rust's built-in testing framework. It
+  covers `googletest`, snapshot testing, mocking as well as how to write your
+  own custom test harness.
 - [Beginner's Series to Rust](https://docs.microsoft.com/en-us/shows/beginners-series-to-rust/)
   and
   [Take your first steps with Rust](https://docs.microsoft.com/en-us/learn/paths/rust-first-steps/):