Support `TEXTBLOCK` directive

[cirras]

Prerequisites

• This improvement has not already been suggested.
• This improvement would be generally useful, not specific to my code or setup.

Engine area

Delphi language support

Improvement description

A new (undocumented) TEXTBLOCK directive was introduced in Delphi 12.

Example: {$TEXTBLOCK NATIVE/CR/LF/CRLF [<ident>]}

See:

• https://blogs.embarcadero.com/yukon-beta-blog-delphi-language-modernizing-string-literals/#Update_Whats_the_formatting_of_the_string_above_Bonus_feature_TEXTBLOCK_directive

Rationale

This is required to properly read the multiline string literals introduced in Delphi 12.