fix inconistent docs

From `check()`:

```
> checking for code/documentation mismatches ... WARNING
Codoc mismatches from documentation object 'big_aggregate':
big_aggregate
Code: function(x, exclude = NULL, output = NULL, exclude_chi = FALSE)
Docs: function(x, exclude = NULL, output = NULL)
Argument names in code not in docs:
exclude_chi

> checking Rd \usage sections ... WARNING
Undocumented arguments in documentation object 'join_full_audio_video'
‘output_name’ ‘keep_na’ ‘keep_comments’
Documented arguments not in \usage in documentation object 'join_full_audio_video':
‘output’

Functions with \usage entries need to have the appropriate \alias
entries, and all their arguments documented.
The \usage entries must correspond to syntactically valid R code.
See chapter ‘Writing R documentation files’ in the ‘Writing R
Extensions’ manual.
```

Search the repository for the documentation objects `big_aggregate` and `join_full_audio_video`, then review their R documentation and the corresponding function signatures. Run `check()` before and after aligning the documented arguments and usage entries; done means these documentation mismatch and undocumented-argument warnings are resolved.

Written by the indexing model from the issue text.