align_vertically moved lines and glyphs but not TextLayout::inlines, so inline
symbols in a centred or bottom-aligned area stayed where top alignment put them.
The reflow path for non-rectangular frames also kept the previous pass's
inlines, drawing each symbol twice.
Document symbols placed inline in a run of type (beyond Illustrator; like
InDesign inline anchored objects): TextRun.inline holds the symbol, scale and
shift; the run is one U+FFFC laid out as a glyph sized to the art, centred on
the cap height. text.insertInline and Type > Insert Inline Symbol; editing
keeps the graphic whole; canvas, SVG (<use>) and PDF draw the art; Create
Outlines turns it into a symbol instance.
haven