linter.fugue.sigIndent

Signature continuation lines: a line that carries binders/hypotheses indents two past the declaration keyword, and the line that carries the statement itself — after the top-level : — indents four, so the statement stays visually distinct from what it quantifies over.

default := false: most existing signatures in the tree put their binders at four, so this carries a large backlog and is opt-in until that is worked through.