Optional ReadonlyerrorOnly set on INVALID tokens. Human-readable explanation of what went
wrong at range.start. Other token kinds leave this undefined.
ReadonlykindReadonlyleadingWhitespace / comments / suppressed newlines preceding the lexeme.
ReadonlylexemeVerbatim source slice for the token itself (without trivia).
ReadonlyrangeSpan of the lexeme itself in the source file. Does not include trivia.
ReadonlytrailingSame-line whitespace / comment trailing the lexeme, up to (but not including) the next newline or non-trivia character.
One lexical token. The lex-rejoin invariant on a token stream
tsis: