refactor!: `vim.lsp.inlay_hint()` -> `vim.lsp.inlay_hint.enable()`

Problem:
The LSP specification allows inlay hints to include tooltips, clickable
label parts, and code actions; but Neovim provides no API to query for
these.

Solution:
Add minimal viable extension point from which plugins can query for
inlay hints in a range, in order to build functionality on top of.

Possible Next Steps
---

- Add `virt_text_idx` field to `vim.fn.getmousepos()` return value, for
  usage in mappings of `<LeftMouse>`, `<C-LeftMouse>`, etc

This avoid the hang mentioned in #24888, and also matches TUI better.

Semi-regression. The "ruler" behavior for a floating window
was never really specified but in practice followed the users
cursor movements in normal mode in a focused float, which seems
like a reasonable behavior to now specify.

scroll_delta contains how much the top line of a window moved since the
last time win_viewport was emitted. It is expected to be used to
implement smooth scrolling. For this purpose it only counts "virtual" or
"displayed" so folds should count as one line. Because of this it
adds extra information that cannot be computed from the topline
parameter.

Fixes #19227

Problem:
In a success-failure-success situation, if minimal timeout is reached
between the failure and the second success, the session is stopped
without waiting for the second success, causing the test to fail.

Solution:
Wait for another success if a failure is seen after a success.

Ref #22155 #22464

Include the rest of the line and allow multiple {MATCH:} patterns.

Problem:
The sleep before collecting the initial screen state is confusing and
may lead to unexpected success if it comes after a blocking RPC call.

Solution:
Remove that sleep and add an "intermediate" argument.