As part of OpenMP Version 5.1, support for the `indirect` clause was
added for the `declare target` directive. This clause should follow an
`enter` clause, and allows procedure calls to be done indirectly through
OpenMP.
This adds Parsing support for the clause, along with semantics checks.
Currently, lowering for the clause is not supported so a TODO message
will be outputted to the user. It also performs version checking as
`indirect` is only support in OpenMP 5.1 or greater.
See also: #110008
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