Incorrect parsing of hard line break in markdown

[oxinabox]

Both the spec for Github Flavoured Markdown and CommonMark state:

A line break (not in a code span or HTML tag) that is preceded by two or more spaces and does not occur at the end of a block is parsed as a hard line break (rendered in HTML as a
tag):

But if you write such code in Julia, that new line is just replaced with a space; as if it were not preceded by two spaces in the source.

julia> md"foo
       bar".content
1-element Vector{Any}:
 Markdown.Paragraph(Any["foo   bar"])

The correct output would be

1-element Vector{Any}:
Markdown.Paragraph(Any["foo\nbar"])

This forces extra line breaks in #39093 as there is no way to have a linebreak without inserting a full blank line (i.e. making two Markdown.Paragraphs)

[mgkuhn]

Git diff (by highlighting them in red) and many programming style guidelines discourage trailing whitespace in source code. Many authors will use editor functions (such as M-x delete-trailing-whitespace in emacs) to remove trailing whitespace, as most of it is added accidentally and considered bad style. Supporting trailing whitespace as part of the Julia source-code syntax seems like a bad idea to me. It will get removed by accident very frequently.

[oxinabox]

This is true, I am not at all a fan of this part of the markdown; but i didn't write it.
We do need a way to insert hardline break.
We could allow <br> /<br/> to be used.
which is what i normally do when using markdown engines that suppprt HTML

[MichaelHatherly]

Related: #16004

[oxinabox]

Related: #16004

seems like this is an outright duplicate