Syntax/Pascal: Support multiline strings

[baka0815]

Delphi introduced multiline strings in version 12. They start with ''' and end with ``'''```.
Supersedes #2720.

Before:

After:

@sdottaka is there a better constant that COOKIE_BLOCK_STYLE to use?

[sdottaka]

Thank you for the correction. However, according to this blog, there are the following rules:

• It is introduced by a triple quote ('''') and a new line (so no text following the triple quotes on the same line)

• It can encompass multiple lines of the source code file (with no limitation)

• It ends with a closing triple quote ('''') in a line without any text preceding it

The current implementation does not seem to follow these rules, and the following is also considered to be multiline strings.
(I'm not familiar with Pascal, so I don't know if the following lines are syntactically correct.)

a = Char('''a');

[baka0815]

You're technically right.

This is how it looks in Delphi 12.3 (my color schema):

Text after the starting or before the ending triple quote will result in compile errors, however it does not affect the syntax highlighting:

However you're right, that var L := Length('''a'); will be treated as the start of the multi-line string where it should be a single quote and an a ('a).

[baka0815]

@sdottaka I changed the code to detect text following the start of the multi-line string. This is then not exactly what Delphi renders, but since this would be a syntax error, I think it's fine.

[sdottaka]

There's one more thing I'd like you to fix. d := 1 should be considered a multiline string, but it isn't.
If there are any other issues, I'll adjust them.

[baka0815]

Well, Delphi does not really know what it wants to do here:

It colors the text as a multi-line string, but at the same time gives the error E2658.

With my latest commit the coloring is ok in WinMerge (I changed the screenshot in the PR message):

[sdottaka]

Thank you for the fix. I've merged this PR.
I plan to make some additional adjustments later, such as changing COOKIE_BLOCK_STYLE to COOKIE_RAWSTRING.