C++: Suspicious pointer scaling: @precision medium

This query is not producing good enough results to justify `@precision
high`. It's fundamentally looking for a pattern that should correlate
with memory management errors, but it doesn't look for the errors
themselves.

Author: jbj

change-notes/1.22/analysis-cpp.md

@@ -11,6 +11,7 @@
 
 | **Query**                  | **Expected impact**    | **Change**                                                       |
 |----------------------------|------------------------|------------------------------------------------------------------|
+| Suspicious pointer scaling (`cpp/suspicious-pointer-scaling`) | Lower precision | The precision of this query has been reduced to "medium". This coding pattern is used intentionally and safely in a number of real-world projects. Results are no longer displayed on LGTM unless you choose to display them. |
 
 ## Changes to QL libraries
 

cpp/ql/src/Security/CWE/CWE-468/IncorrectPointerScaling.ql

@@ -4,7 +4,7 @@
  *              can cause buffer overflow conditions.
  * @kind problem
  * @problem.severity warning
- * @precision high
+ * @precision medium
  * @id cpp/suspicious-pointer-scaling
  * @tags security
  *       external/cwe/cwe-468