Add documentation for exception matchers.

PiperOrigin-RevId: 775205267
Change-Id: I3ad59ff4b1fa095cbf7dd04dd97a152cb33c7435

Author: Abseil Team

docs/reference/matchers.md

@@ -111,6 +111,33 @@ use the regular expression syntax defined
 [here](../advanced.md#regular-expression-syntax). All of these matchers, except
 `ContainsRegex()` and `MatchesRegex()` work for wide strings as well.
 
+## Exception Matchers
+
+| Matcher                                   | Description                      |
+| :---------------------------------------- | :------------------------------- |
+| `Throws<E>()` | The `argument` is a callable object that, when called, throws an exception of the expected type `E`. |
+| `Throws<E>(m)` | The `argument` is a callable object that, when called, throws an exception of type `E` that satisfies the matcher `m`. |
+| `ThrowsMessage<E>(m)` | The `argument` is a callable object that, when called, throws an exception of type `E` with a message that satisfies the matcher `m`. |
+
+Examples:
+
+```cpp
+auto argument = [] { throw std::runtime_error("error msg"); };
+
+// Checks if the lambda throws a `std::runtime_error`.
+EXPECT_THAT(argument, Throws<std::runtime_error>());
+
+// Checks if the lambda throws a `std::runtime_error` with a specific message
+// that matches "error msg".
+EXPECT_THAT(argument,
+            Throws<std::runtime_error>(Property(&std::runtime_error::what,
+                                                Eq("error msg"))));
+
+// Checks if the lambda throws a `std::runtime_error` with a message that
+// contains "msg".
+EXPECT_THAT(argument, ThrowsMessage<std::runtime_error>(HasSubstr("msg")));
+```
+
 ## Container Matchers
 
 Most STL-style containers support `==`, so you can use `Eq(expected_container)`