Preserve comments in `--fmt`

[casey]

--fmt and --dump should preserve all comments, including ones that follow items, like this one:

alias x := y # foo

[eigengrau]

A related case is comments preceding a recipe, as in:

# Does internal stuff.
# Internal stuff so complex the comment has two lines.
_internal: …

Which will be formatted as:

# Does internal stuff.

# Internal stuff so complex the comment has two lines.
_internal: …

[MaxFangX]

+1, the comments preceding recipes getting misformatted when they are multi-line has been a minor point of friction for us. We use just --fmt --unstable in our CI so some of our multi-line comments look pretty weird.

For example the recipe mentioned in #1337 gets formatted to this:

# Build python image for ARM arhcitecture.
#
# We are building directly by docker command, because docker-compsoe doesn't support

# different Dockerfiles for different processor architectures
build-python-arm-image:
    docker build --file config/docker/py.ARM.dockerfile --target dev --tag my-image .

[casey]

Trailing and internal comments are still not preserved, but the issue of multi-line comments before recipes getting broken up is now fixed. The actual change was #3274, which changed how newlines and spacing between items is handled, and I added a test in #3276 that mutli-line recipe comments are not broken up.

[casey]

Also, @eigengrau, great username!

[casey]

Fixed in #3282.

[MaxFangX]

Great work, thanks a ton @casey!

[casey]

@MaxFangX Thanks, better late than never!