trim each line when printing update reminder

[cfbao]

Why

The update reminder's background area is misaligned on Windows:

This is because we didn't account for \r on Windows.
Still a mystery why this only happens with GitHub Actions' build but not with our local builds. Regardless, this fix works with both.

Ticket

https://desire2learn.atlassian.net/browse/VUL-447

[cfbao]

OMG... I know why.

Which newline string is used (LF vs CRLF) in raw string literals is determined by which one you use in the source file (well... they are "literals").
E.g. given the source code

string s = """
	1
	2
	""";
Console.WriteLine(
	Convert.ToHexString(System.Text.Encoding.UTF8.GetBytes(s))
);

the program will

• print 310A32 if the file uses LF as newline characters
• print 310D0A32 if the file uses CRLF as newline characters

On our dev machines, we set core.autocrlf=false in Git and have end_of_line = lf in .editorconfig, so we always have LF as newline characters.
GitHub Actions Windows runners seems to be using core.autocrlf=true, so all source files are cloned with CRLF line endings...(!!!) and hence the executables built has different behaviour, because it doesn't use equivalent source code!