blog: correct punctuation in why-generics

Change-Id: I4aa338da4a711817ce1ccc79778e119bdedb6345
Reviewed-on: https://go-review.googlesource.com/c/website/+/343251
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/go.dev/_content/blog/why-generics.md b/go.dev/_content/blog/why-generics.md
index d1a0c91..776c60d 100644
--- a/go.dev/_content/blog/why-generics.md
+++ b/go.dev/_content/blog/why-generics.md
@@ -607,7 +607,7 @@
 It lets the caller of the generic function clearly see whether the
 function is applicable for the types being used.
 
-In practice this contract would probably go into the standard library.
+In practice this contract would probably go into the standard library,
 and so really the Min function (which will probably also be in the
 standard library somewhere) will look like this.  Here we're just
 referring to the contract Ordered defined in the package contracts.