DescriptorNeverClosed.ql identifies only sockets (not file handles) #2623

Description of the issue
The wiki description for the DescriptorNeverClosed Library
(URL: https://help.semmle.com/wiki/display/CCPPOBJ/Open+descriptor+never+closed)
states that this library identifies both socket handles and file handles that have not been
closed. However, it appears the query only searches for socket handles that have not been closed.

In the DescriptorNeverClosed.ql file (URL: https://github.com/Semmle/ql/blob/master/cpp/ql/src/Critical/DescriptorNeverClosed.ql)
the handles being search for by the query are initially acquired with the allocateDescriptorCall predicate that appears in the where clause (line 29 of the DescriptorNeverClosed.ql file).

However, the implementation of this predicate, which is found in https://github.com/Semmle/ql/blob/3a95cd5e9c15f02208c73d3972f6283a27ca8657/cpp/ql/src/semmle/code/cpp/pointsto/PointsTo.qll

has the following implementation - which only searches for socket handles (starting line 699):

predicate allocateDescriptorCall(FunctionCall fc) {
exists(string name |
name = "socket" and
fc.getTarget().hasGlobalName(name)
)
}