{yang_models]: Updated SONiC YANG extensions as per guidelines.

Author: maheshwari-mayank

src/sonic-yang-models/yang-models/sonic-extension.yang

@@ -44,13 +44,10 @@ module sonic-extension {
         argument "value";
     }
 
-    extension map-list {
-        description "If it is a map list";
-        argument "value";
-    }
-
     extension map-leaf {
-        description "Map leaf names";
+        description
+           "Extension to indicate nested list and specify fields
+           mappings which are keys of inner list";
         argument "value";
     }
 
@@ -61,7 +58,7 @@ module sonic-extension {
 
     extension dependent-on {
         description
-            "Entension to define dependency on other table. During create/update,
+            "Extension to define dependency on other table. During create/update,
             operation will be performed first on parent table and then on this table.
             In delete operation, this table will be deleted first and then parent table.
             This extension can be defined only under list. Table name should always

src/sonic-yang-models/yang-models/sonic-types.yang

@@ -148,16 +148,16 @@ module sonic-types {
             "Integer indicating a percentage value";
     }
 
-	// Defined as container because it will be used as xpath in MUST/WHEN
-	// expressions in yang.
-	container operation {
-		leaf operation {
-			type enumeration {
-				enum CREATE;
-				enum UPDATE;
-				enum DELETE;
-			}
-		}
-		description "Sonic data operation types required during validation";
-	}
+    // Defined as container because it will be used as xpath in MUST/WHEN
+    // expressions in yang.
+    container operation {
+        leaf operation {
+            type enumeration {
+                enum CREATE;
+                enum UPDATE;
+                enum DELETE;
+            }
+        }
+        description "Sonic data operation types required during validation";
+    }
 }