Remove trailing whitespace in multi-line string literals of tests

[ahoppen]

In mulit-line string literal tests these trailing whitespaces are really hard to spot but influence the test significantly. To make them more obvious, use \u{20}, which is visible in the editor and will be replaced by a normal space in AssertParse

In all other cases where the trailing whitespace doesn’t matter, remove it.

[ahoppen]

@swift-ci Please test

[bnbarham]

How many tests actually need this? Rintaro suggested that we could just have this inline on each of the tests instead. I'd also prefer it not be replaced with anything (ie. replace with empty string) and just be a marker for "keep this whitespace".

[allevato]

FWIW, in swift-format we just write literal \u{0020} in any strings where we want to trailing space to be explicit, visible, and not removed automatically by tooling, and that doesn't require any custom logic for replacement: https://github.com/apple/swift-format/blob/3cd655ff323bd22be523dd33b5e1cd0b14f6bf0a/Tests/SwiftFormatPrettyPrintTests/CommentTests.swift#L651

[ahoppen]

I like the idea of using \u{20} and adopted that.

[ahoppen]

@swift-ci Please test

[ahoppen]

@swift-ci Please test

[bnbarham]

The commit comment doesn't really apply now, but looks good otherwise.

which is visible in the editor and will be replaced by a normal space in AssertParse

It's not really "replaced" by AssertParse any more - just by the compiler 😅.

[ahoppen]

Oh, I changed the commit message, just forgot to update the PR description.

[ahoppen]

@swift-ci Please test macOS

[bnbarham]

Oh, I changed the commit message, just forgot to update the PR description.

I was referring to the commit message as well, FWIW.