Problem: There is no way for a `vim.ui.input` caller to indicate for
which scope the input is. As in "This input is for something at cursor
scope". This information can be useful for `vim.ui.input`
implementation to tweak its behavior and presentation:
- Show different floating window depending on the scope. For example:
- Near cursor for "cursor" scope.
- At line start for "line" scope.
- In window corner for "buffer" and "window" scopes.
- In whole editor corner for "tabpage", "editor", "project" scopes.
- Navigate through history only for inputs with the same scope.
Solution: Document new `opts.scope` for `vim.ui.input`. Use it in the
codebase.
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