Feature request: Infer `@private` for #-prefixed private methods

[LeaVerou]

I was surprised I had to add @private for #-prefixed functions to be recognized as private, it seems relatively straightforward to infer.

Possibly related: #1355

[tannerstern]

I was going to suggest using the --infer-private option with --infer-private "^#" but for whatever reason that doesn't work. In the output it appears the # character is stripped from function names some time before the "infer access" step. I tried again with --infer-private "^_" as exampled in the source code which did work as expected.