Improve function detection regex to avoid the necessity of multi-step checks

Bellwether example:

`const uint8_t (*OutPoint_get_txid(const struct LDKOutPoint *NONNULL_PTR this_ptr))[32];`

Old example that still also needs to work:

`uint16_t OutPoint_get_index(const struct LDKOutPoint *NONNULL_PTR this_ptr);`

No file or test is named. Start by locating the function-detection regex in the Swift parser and compare its behavior against both declarations in the issue; done means one detection pass recognizes the pointer-returning declaration while preserving detection of the uint16_t example.

Written by the indexing model from the issue text.