Fixed typo in readme

ronbo · mpirnat · commit f34228503b20 · 2019-06-12T17:04:16.000-04:00
diff --git a/README.rst b/README.rst
@@ -105,7 +105,7 @@ Apparently a test failed::
 
     AssertionError: False is not True
 
-It also tells me exactly where the problem in, its an assert on line 12
+It also tells me exactly where the problem is, it's an assert on line 12
 of .\\koans\\about_asserts.py. This one is easy, just change False to True to
 make the test pass.
 
