Over-indent multiline interpolations

[dralletje]

I made this PR after needing the same features as #12

It looks at the value in interpolations and adds the indentation to every but the first line (because that one already has the indentation).

I'm not sure if you'd want this in the package, as it assumes a lot more stuff, but on the other hand I can not imagine a scenario where you don't want this 🙃

[rattrayalex-stripe]

Probably worth adding a test like the one referenced in #12 , namely:

const weird = dedent`
  foo.
  ${[1,2,3].map(x => dedent`
    hello
      world
  `).join('\n')}
  bar.
`;

which should produce (as it does):

foo.
hello
  world
hello
  world
hello
  world
bar.

Possibly also

const weirder = dedent`
  foo.
    ${[1,2,3].map(x => dedent`
      hello
        world
    `).join('\n')}
  bar.
`;

which I think should produce

foo.
  hello
    world
  hello
    world
  hello
    world
bar.

[dralletje]

I feel these extra tests are not necessary, as this is covered by the 'non-map' version of the tests... dunno how the author feels about tests testing the same thing :P

[rattrayalex-stripe]

... Yes, you're correct; I wasn't reading very carefully. Thanks!

The inner template should probably include indents/dedents, though, eg;

dd`
  first
    ${dd`
         second
       third
           fourth
    `}
  fifth
`

to ensure that "inner template" logic is the same as "outer template" logic

[rattrayalex-stripe]

(to be clear, I think the above is purely optional and I would expect it to pass today)

[dralletje]

Added another commit to make a bit more strict

[rattrayalex-stripe]

cc @dmnd is this mergeable?

[ZhouHansen]

Hi! @rattrayalex-stripe you can use endent to achieve what you want before this pr merged.

[JoshuaKGoldberg]

Note: I posted a question in #12 about whether we want this to always be the case, or an opt-in.

[JoshuaKGoldberg]

Closing for now to keep the queue small - let's discuss in #12. Cheers!