outer_lag_newlines are added to the first token in pd,
outer_indent is added to all tokens in pd, outer_spaces is added to
the last token in pd. context_to_terminals() calls this function
repeatedly, which means the propagation of the parse information to the
terminal tokens.
context_towards_terminals(pd_nested, outer_lag_newlines, outer_indent,
  outer_spaces, outer_indention_refs)A nested parse table.
The lag_newlines to be propagated inwards.
The indention depth to be propagated inwards.
The number of spaces to be propagated inwards.
The reference pos id that should be propagated inwards.
An updated parse table.
context_to_terminals