Introduce a new `BlockStyle` field for blocks

This new field allows blocks to specify how they want to be laid out:

- If `Fixed` they can take up all the width they want and they will impact
the scroll width of the editor. This is useful for diagnostic messages and
allows scrolling the editor further to the right to visualize the entire message.
- If `Flex` they can extend all the way to the scroll width without impacting it
any further. This is useful for the rename editor that we insert as a block
decoration when hitting `F2`.
- If `Sticky`, they will be as wide as the editor element and won't participate
in the horizontal scrolling of the editor. This is useful for headers in general,
where we want e.g. the filename and the jump button to always be visible
independently of how much the user has scrolled to the right.

Always delay hover display

Hover fixes. Addresses delay issues with current hover implementation, shrinks the hover popover, and tweaks the display of markdown data

Add Go support

We only support additionalEdits if they are provided when resolving the
completion, not if they are provided immediately.

Snap overlay's bottom/right edge to same window's edge on overflow

Introduce a new language-overrideable `enable_language_server` setting

This will be useful later to stop a language server when detecting
configuration changes.

Show "Jump to Buffer" icon on every excerpt header

* Add a `hard_tabs` setting that causes indentation to be performed
  using a tab instead of multiple spaces.
* Change Buffer's indentation-related APIs to return an `IndentSize`
  struct with a length and a kind, instead of just a single u32.
* Use hard tabs by default in Go.

Co-authored-by: Antonio Scandurra <me@as-cii.com>

Co-authored-by: Antonio Scandurra <me@as-cii.com>

Co-authored-by: Antonio Scandurra <me@as-cii.com>

This lays the groundwork for adding an optional `primary` field that can
be supplied to provide the "jump to" feature.

Use visible bounds to determine hit bounds for cursor/mouse regions

Provide `tab_size` when formatting document using LSP range formatting

Reduce log level on `collab`

This is generating way too much data and doesn't seem very cost-effective
to investigate the issues we've had with the stale contacts panel.