Fix typos and lints. (#400)

diff --git a/go/pkg/client/tree_test.go b/go/pkg/client/tree_test.go
index 4f07230..2b6c19b 100644
--- a/go/pkg/client/tree_test.go
+++ b/go/pkg/client/tree_test.go
@@ -171,7 +171,7 @@
 		}
 		return rootDg, cache.calls
 	}
-	// call ComputeMerkleTree with working dir = "out/bar" and remote working dir not overriden
+	// call ComputeMerkleTree with working dir = "out/bar" and remote working dir not overridden
 	// inputs contain a file and a non-empty dir in the working directory, and a file and a non-empty dir outside of the working directory
 	referenceDg, _ := callComputeMerkleTree([]string{"out/bar/a", "out/bar/foo/b", "c", "bar/baz/d"},
 		[]string{"out/bar/a", "out/bar/foo", "c", "bar/baz"}, []*command.VirtualInput{{Path: "out/bar/baz", IsEmptyDirectory: true}}, "out/bar", "")
diff --git a/go/pkg/fakes/server.go b/go/pkg/fakes/server.go
index 9182dcc..c58eb52 100644
--- a/go/pkg/fakes/server.go
+++ b/go/pkg/fakes/server.go
@@ -307,7 +307,7 @@
 	return nil
 }
 
-// Builds the directory tree by recursively iterating through the directory.
+// BuildDir builds the directory tree by recursively iterating through the directory.
 // This is similar to tree.go ComputeMerkleTree.
 func BuildDir(path string, s *Server, execRoot string) (root *repb.Directory, childDir []*repb.Directory, err error) {
 	res := &repb.Directory{}
diff --git a/go/pkg/filemetadata/filemetadata.go b/go/pkg/filemetadata/filemetadata.go
index 592a95e..7f82121 100644
--- a/go/pkg/filemetadata/filemetadata.go
+++ b/go/pkg/filemetadata/filemetadata.go
@@ -49,8 +49,10 @@
 }
 
 var (
+	// XattrDigestName is the xattr name for the object digest.
 	XattrDigestName string
-	XattrAccess     xattributeAccessorInterface = xattributeAccessor{}
+	// XattrAccess is the object to control access of XattrDigestName.
+	XattrAccess xattributeAccessorInterface = xattributeAccessor{}
 )
 
 // Error returns the error message.
diff --git a/go/pkg/tool/tool.go b/go/pkg/tool/tool.go
index b40dd44..a27b612 100644
--- a/go/pkg/tool/tool.go
+++ b/go/pkg/tool/tool.go
@@ -408,7 +408,7 @@
 	return digest.NewFromBlob(acPb).String(), nil
 }
 
-// ExecuteAction executes an action in a cannonical structure remotely.
+// ExecuteAction executes an action in a canonical structure remotely.
 // The structure is the same as that produced by DownloadAction.
 // top level >
 //           > ac.textproto (Action text proto)