Funtion name with variable part in doc/man7/ and doc/internal/man3/

Funtion name with variable part in doc/man7/ and doc/internal/man3/

We have a few pages where part of function names can be considered
variable.  There are no normative guidelines for such a case, but if
we draw from the formatting convention of variable and argument names,
we can draw the conclusion that this variable part should be italized,
within already given conventions.  In other words, we need to help the
POD processor along in cases like these:

    SPARSE_ARRAY_OF(TYPE)
    ossl_sa_TYPE_num()

These need explicit formatting:

    B<SPARSE_ARRAY_OF>(I<TYPE>)
    B<ossl_sa_I<TYPE>_num>()

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/10034)