Methods called `<type name><integer>` will be interpreted as constructors

In `fun/mod.rs` we look for an integer suffix to the type name, and if it's there, we assume it's a constructor.

We might need more metadata from `autocxx-bindgen` to do better.

Start in fun/mod.rs, where integer suffixes on type names are used to identify constructors. Then inspect the metadata provided by autocxx-bindgen to determine whether it can distinguish these methods more reliably. Done means methods named with a type name followed by an integer are no longer incorrectly interpreted as constructors.

Written by the indexing model from the issue text.