There might legitimately be "|" characters in the message, so
we want to stop at the first one, the one that delimits the message location
from the message text.
Don't ask Kakoune to quote values we know can never contain shell-sensitive
characters, and flatten the kakquote() function to a single line for ease
of copy/pasting.
Fixes#2302, #3336.
Addresses parts of #3155.
Changes include:
- New `lint-selections` command that only lints the current selections,
and allows a custom lint command.
- New `lint-buffer` command that always lints the whole buffer with
the linter specified in the lintcmd option.
- `lint` alias for `lint-buffer`, for backwards compatibility.
- Errors and warnings are now shown in the Error and Information faces,
not hard-coded red and yellow.
- Error and warning flags now use "!" and "?" symbols respectively,
instead of a unicode block, so they can still be distinguished
in a monochrome colour-scheme or by colour-blind users.
- An error flag on a given line always takes precedence over a warning.
- All messages for the same line are collected into a multi-line message.
- We no longer escape tildes in messages, since that change was added
in commit ae339dc (2016) when we started using `%~~` to quote messages.
We stopped using `%~~` in commit 1a2eecd (2018).
- Anything the linter writes to stderr is logged to the *debug* buffer,
not lost.
- If the linter writes to stderr, an error is shown to the user instead
of the usual error/warning count.
- The `lint_errors` hidden option is replaced by `lint_messages`,
because it contains warnings as well as errors.
- `lint-next-error` renamed to `lint-next-message`,
and `lint-previous-error` renamed to `lint-previous-message`
for the same reason.
- New `lint-next-error` and `lint-previous-error` aliases,
for backwards compatibility.
- `lint-next-message` and `lint-previous-message` show the message
they jump to.
- Where `lint_errors` was a range-specs option, `lint_messages` is a
line-specs option to keep things simpler. This means lint-next-message
and lint-previous-message no longer jump to a specific column.
