🔭 Trim end of line only in directives (important for code-blocks)

[rowanc1]

This code block now has indentation at the start. Previously it was trimmed.

```{code-block} c
:linenos: true
:lineno-start: 2
:emphasize-lines: 3
    for (int i = 0; i < 10; i++) {
        /* do something */
    }
```

[fwkoch]

I think this change is fine: trim() on the directive content is problematic with leading spaces, using trimEnd() keeps leading spaces but makes the change slightly smaller since we are not entirely eliminating the trim.

My only suggestion is that the PR title and the changeset are misleading. This "trim end of line only" applies to all directives, not just code-block.

[fwkoch]

Not totally clear why we need this, without digging into it...? Is there, like, some test-case round-tripping that does not work any more?

[rowanc1]

There are some of these defined in the myst-spec!

[fwkoch]

Yeah, ok - so the trim() originally came from respecting those tests, now we no longer totally align with them. (Well, there are already a few ways we don't align with them, this is just one more, not a big deal...)