gotypes: fix plural

Change-Id: I1496492af6f87cfe3cedcb772cbf112dcc5f55f8
Reviewed-on: https://go-review.googlesource.com/18231
Reviewed-by: Alan Donovan <adonovan@google.com>

gotypes/README.md

@@ -349,7 +349,7 @@ imported from such a file returns zero, also known as
 
 
 
-There are eight kinds of object in the Go type checker.
+There are eight kinds of objects in the Go type checker.
 Most familiar are the kinds that can be declared at package level:
 constants, variables, functions, and types.
 Less familiar are statement labels, imported package names

gotypes/go-types.md

@@ -266,7 +266,7 @@ imported from such a file returns zero, also known as
 
 
 
-There are eight kinds of object in the Go type checker.
+There are eight kinds of objects in the Go type checker.
 Most familiar are the kinds that can be declared at package level:
 constants, variables, functions, and types.
 Less familiar are statement labels, imported package names