Adjust precision of existing rule and add a supplementary rule

Author: jeongsoolee09

rule_packages/cpp/Memory1.json

@@ -10,12 +10,23 @@
           "description": "Pointers obtained as result of performing arithmetic should point to an initialized object, or an element right next to the last element of an array.",
           "kind": "problem",
           "name": "Pointer arithmetic shall not form an invalid pointer.",
-          "precision": "very-high",
+          "precision": "high",
           "severity": "error",
           "short_name": "PointerArithmeticFormsAnInvalidPointer",
           "tags": [
             "scope/system"
           ]
+        },
+        {
+          "description": "Pointer and index arguments passed to functions in <cstring> should result in valid reads and/or writes.",
+          "kind": "problem",
+          "name": "Pointer and index arguments passed to functions in <cstring> shall not be invalid.",
+          "precision": "high",
+          "severity": "error",
+          "short_name": "PointerArgumentToCstringFunctionIsInvalid",
+          "tags": [
+            "scope/system"
+          ]
         }
       ],
       "title": "Pointers obtained as result of performing arithmetic should point to an initialized object, or an element right next to the last element of an array."