cmd/go: fix unnecessary plural

"expanded imports paths" should read "expanded import paths." Run
mkalldocs.sh to pick up other changes which were not committed to
alldocs.go.

Change-Id: Iaa61e022d65f9464e8ff93a92cfba27dadf679cf
Reviewed-on: https://go-review.googlesource.com/127157
Reviewed-by: Brad Fitzpatrick <[email protected]>

Author: kevinburke

src/cmd/go/alldocs.go

@@ -107,7 +107,7 @@ Packages stored in vendor directories report an ImportPath that includes the
 path to the vendor directory (for example, "d/vendor/p" instead of "p"),
 so that the ImportPath uniquely identifies a given copy of a package.
 The Imports, Deps, TestImports, and XTestImports lists also contain these
-expanded imports paths. See golang.org/s/go15vendor for more about vendoring.
+expanded import paths. See golang.org/s/go15vendor for more about vendoring.
 
 The error information, if any, is