add helper method for parsing multiline String to DslParams

[ChongHan]

as title

[swarren12]

I wonder if it would be preferable to use a more explicit name for the new method? I think it's highly unlikely that overloading would cause problems for anyone, but might be better to err on the side of caution.

createMultiline() or similar, just to make it explicit what's going on.

[ags313]

No tests?

[ChongHan]

test added; plus fixed a bug

[ChongHan]

I wonder if it would be preferable to use a more explicit name for the new method? I think it's highly unlikely that overloading would cause problems for anyone, but might be better to err on the side of caution.

createMultiline() or similar, just to make it explicit what's going on.

I'm neutral on this, splitting "arg\n" by line terminator should still safely produce "arg", and it's more code to change if you want to migrate a legacy codebase to use text blocks. Maybe a poll in tfxdev?