[AT] Fix typos in Kconfig

components/net/at/Kconfig

@@ -75,7 +75,7 @@ if RT_USING_AT
             default n
 
         config AT_CMD_MAX_LEN
-            int "The maximum lenght of AT Commonds buffer"
+            int "The maximum lenght of AT Commands buffer"
             default 128
 
     endif