Trivial typo fix. (#1119)
diff --git a/docs/assertions.md b/docs/assertions.md
index 93f88c4..ece4e10 100644
--- a/docs/assertions.md
+++ b/docs/assertions.md
@@ -21,7 +21,7 @@
* **REQUIRE(** _expression_ **)** and
* **CHECK(** _expression_ **)**
-Evaluates the expression and records the result. If an exception is thrown it is caught, reported, and counted as a failure. These are the macros you will use most of the time
+Evaluates the expression and records the result. If an exception is thrown, it is caught, reported, and counted as a failure. These are the macros you will use most of the time.
Examples:
```