Fraction of pane height kept empty at top/bottom (default 0.1 each).
Instrument tick size (minMove), e.g. 0.05. 0 → infer from range.
A property of the instrument and not of the axis, so it belongs only on a
scale that quotes one. An oscillator's pane reads in its own units and is
left at 0 there, which is why Chart.setPriceScaleOptions withholds it
from those panes rather than broadcasting it like the rest of this block.
Least decimals a scale with no tick will print. 0 leaves the span to
decide alone, which is right for a price axis and too coarse for a bounded
oscillator: see precision().
Ignored once minMove is set, because a declared tick is a stronger
statement about the instrument than a floor is about the axis.
Linear, logarithmic or rebased (percentage / indexed-to-100) price↔y mapping.
Flip the axis (price increases downward) — for spread/short views.