Indentation-sensitive block: @indent(expr) / @samecol(expr).
Both pragmas produce this node; kind distinguishes them since their
runtime checks differ -- @indent requires a column strictly greater
than the current reference column and resets the reference column to
the first matched token's column, @samecol requires exactly the
current reference column.
Summary
Types
@type t() :: %Grammar.IR.Indent{ expr: Grammar.IR.expr(), kind: :indent | :samecol, meta: Grammar.IR.Meta.t() }