[Feature Request]: Rename validate_inputs function or deprecate it

### Feature description

Function `validate_inputs` has a name too similar to `validate_input`. But the inner behavior and usage is different, which might create confusion among users. I suggest:
1. Rename `validate_inputs` to `validate_shiny_input` or a name that is different enough from `validate_input` so it is clear for the user that they are different functions
2. Deprecate `validate_inputs` as `validate_input` covers all its use cases. `validate_inputs` is only useful for apps that use `shinyvalidate` package.

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct.

### Contribution Guidelines

- [x] I agree to follow this project's Contribution Guidelines.

### Security Policy

- [x] I agree to follow this project's Security Policy.

Start by locating the validate_inputs and validate_input definitions and all references in the repository. Compare their usage, especially where shinyvalidate is involved, then clarify whether the project wants a distinct name or deprecation before updating the affected public API references.

Written by the indexing model from the issue text.