Remove stray backticks to fix end of code block in testing documentation.

Also replaced ```` with ``` in other document where it didn't cause a visible change.

PiperOrigin-RevId: 205112255

site/docs/skylark/testing.md

diff --git a/site/docs/skylark/testing.md b/site/docs/skylark/testing.md
index f1a9225..5957e6d 100644
--- a/site/docs/skylark/testing.md
+++ b/site/docs/skylark/testing.md
@@ -133,7 +133,7 @@
           # ...
       ],
   )
-````
+```
 
 The test can be run with `bazel test //mypkg:myrules_test`.
 
@@ -442,7 +442,7 @@
     myhelper_test,
     # ...
   )
-````
+```
 
 For more examples, see Skylib’s own [tests](https://github.com/bazelbuild/bazel-skylib/blob/master/tests/BUILD).