Fix goreportcard issues (#271)

* Fixed misspell

* Fixed ineffassign

`user` and `password` always got overwritten
`orderedVals` was initialized with an empty array but always got overwritten by either `sortByLines()` or `sortAlphabetical`
`err` was assigned a `nil` value that was either overwritten or unused anyways

* Fix comment for DeletePath

The comment assumed the method was named Delete, i guess a rename happened at some point

* Update doc_test.go

keysparsing_test.go

@@ -24,7 +24,7 @@ func testResult(t *testing.T, key string, expected []string) {
 func testError(t *testing.T, key string, expectedError string) {
 	res, err := parseKey(key)
 	if err == nil {
-		t.Fatalf("Expected error, but succesfully parsed key %s", res)
+		t.Fatalf("Expected error, but successfully parsed key %s", res)
 	}
 	if fmt.Sprintf("%s", err) != expectedError {
 		t.Fatalf("Expected error \"%s\", but got \"%s\".", expectedError, err)