fix some typos

Signed-off-by: bin liu <liubin0329@gmail.com>

pkg/labels/selector.go

@@ -467,7 +467,7 @@ func (l *Lexer) Lex() (tok Token, lit string) {
 	}
 }
 
-// Parser data structure contains the label selector parser data strucutre
+// Parser data structure contains the label selector parser data structure
 type Parser struct {
 	l            *Lexer
 	scannedItems []ScannedItem