Improvements to C/C++ analysis

General improvements

Query	Tags	Purpose
@name of query (Query ID)	Tags	Aim of the new query and whether it is enabled by default or not

Query	Expected impact	Change
Resource not released in destructor	Fewer false positive results	Placement new is now excluded from the query.
Missing return statement (`cpp/missing-return`)	Visible by default	The precision of this query has been increased from 'medium' to 'high', which makes it visible by default in LGTM. It was 'medium' in release 1.17 and 1.18 because it had false positives due to an extractor bug that was fixed in 1.18.
Call to memory access function may overflow buffer	More correct results	Array indexing with a negative index is now detected by this query.
Suspicious add with sizeof	Fewer false positive results	Arithmetic with void pointers (where allowed) is now excluded from this query.
Wrong type of arguments to formatting function	Fewer false positive results	False positive results involving typedefs have been removed. Expected argument types are determined more accurately, especially for wide string and pointer types. Custom (non-standard) formatting functions are also identified more accurately.