This PR adjusts the "try this" widget to be rendered as a widget message
under 'Messages', not a separate widget under a 'Suggestions' section.
The main benefit of this is that the message of the widget is not
duplicated between 'Messages' and 'Suggestions'.
Since widget message suggestions were already implemented by @jrr6 for
the new hint infrastructure, this PR replaces the old "try this"
implementation with the new hint infrastructure. In doing so, the
`style?` field of suggestions is deprecated, since the hint
infrastructure highlights hints using diff colors, and `style?` also
never saw much use downstream. Additionally, since the message and the
suggestion are now the same component, the `messageData?` field of
suggestions is deprecated as well. Notably, the "Try this:" message
string now also contains a newline and indentation to separate the
suggestion from the rest of the message more clearly and the `postInfo?`
field of the suggestion is now part of the message.
Finally, this PR changes the diff colors used by the hint infrastructure
to be more color-blindness-friendly (insertions are now blue, not green,
and text that remains unchanged is now using the editor foreground color
instead of blue).
### Breaking changes
Tests that use `#guard_msgs` to test the "Try this:" message may need to
be adjusted for the new formatting of the message.
This PR filters out all declarations from `Lean.*`, `*.Tactic.*`, and
`*.Linter.*` from the results of `exact?` and `rw?`.
---------
Co-authored-by: damiano <adomani@gmail.com>
Co-authored-by: Markus Himmel <markus@lean-fro.org>
This PR changes the behaviour of `apply?` so that the `sorry` it uses to
close the goal is non-synthetic. (Recall that correct use of synthetic
sorries requires that the tactic also generates an error message, which
we don't want to do in this situation.) Either this PR or #8230 are
sufficient to defend against the problem reported in #8212.
