feat: Preludes Until, String, Span, Line and EOL

[phorward]

This is the PR for implementing the built-in parselets

• Until
• String
• Span
• Line (Line built-in #38)
• EOL
• Tests

Started with Until.tok draft.
Currently not working due #130. (meanwhile fixed by #166).

---

The original definition from #10:

Until : @<P, Escape: Void>

The Until-parselet parses data until a specific token occurs.

• '"' Until<'"', Escape: '\\'> '"' parse strings like "Hello World" or with escape sequences like "Hello\nWorld"
• Implement a String parselet as shortcut for above, like String: @<Start, End: Void, Escape: Void>
• Until<Not<Char<A-Za-z_>]>> parse anything consisting not of Char<A-Za-z_> INVALID.
• Until<EOF> read all until EOF
• Line built-in #38 refers to a Line parselet for matching input lines

[phorward]

This PR is a dependency for #38

[phorward]

The original attempt of until.tok, which is this:

Until : @<P, Escape: Void, Reject: Void> {
    Peek<P>  accept $0
    (Escape P | Char)  repeat
    Reject?  reject
}

String: @<Start: Char<'">, End: Void, Escape: '\\'> {
    Start Until<(End | Start), Escape> (End | Start)
}

#print(Until<'x', '\\'> 'x')
print("STRING:", String<'"'>)
print(Char)

now works with #166 as expected 💯.