Render: brush art is made again when a symbol or pattern it can show changes

Brush art leaves out the symbol instances and pattern paints whose art
draws a brushed stroke. The brush cache now records whether a brush's art
or the stroke's paint can show a symbol or a pattern, and drops those
entries when the art of the document's symbols or patterns changes, so an
edit that makes a symbol or pattern start or stop drawing a brushed stroke
draws as a new renderer does.

The parity line gives the median and fastest-frame figures of the
benchmark for both documents it names.

docs/target-app-parity.md

@@ -989,7 +989,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
 
 - **Type with transparency or effects:** type at less than 100% opacity, in a blend mode other than Normal, or with raster effects such as a drop shadow keeps its glyph outlines between frames, as opaque type does, and is laid out again when it is edited or the fonts change. At 2880 × 1800 on 8 threads, a page of 1,000 type objects takes 13 ms a frame instead of 23 ms at 80% opacity, 31 ms instead of 41 ms in Multiply and 16 ms instead of 26 ms with a drop shadow, with the same pixels.
 
-- **Brush art of copies:** symbol instances, inline graphics and repeat copies of a brushed path keep their own brush art between frames, as the same path on the page does. The renderer also keeps the stroke outlines of brush art and the evaluation of a live object in it, such as an envelope that a scatter brush places. The brush art is made again when the path, its stroke or the brush changes. On one thread at 1000 × 1000 pixels, 2,000 paths on the page whose scatter brush art is an envelope take 94 ms a frame instead of 400 ms, and the fastest frames of 2,000 instances of a symbol whose art is a brushed path take 12 ms instead of 16 ms, with the same pixels.
+- **Brush art of copies:** symbol instances, inline graphics and repeat copies of a brushed path keep their own brush art between frames, as the same path on the page does. The renderer also keeps the stroke outlines of brush art and the evaluation of a live object in it, such as an envelope that a scatter brush places. The brush art is made again when the path, its stroke or the brush changes, and when the art of a symbol or pattern that the brush art can show changes. On one thread at 1000 × 1000 pixels (the median frame, with the median fastest frame in brackets), 2,000 paths on the page whose scatter brush art is an envelope take 94 ms (80 ms) a frame instead of 400 ms (306 ms), and 2,000 instances of a symbol whose art is a brushed path take 13.4 ms (12.0 ms) instead of 19.3 ms (15.6 ms), with the same pixels.
 
 - **Live objects in symbols and masks:** symbol instances and inline graphics whose symbol is a blend, an envelope, a repeat, an Intertwine object or a gradient mesh, or a group that holds one, draw the evaluation the renderer keeps for that object between frames, as the same object on the page does. So do opacity masks whose art is such an object, and such objects in clip groups in Outline view. The object is evaluated again when the symbols, patterns, fonts or color settings it shows change. Symbol art with effects of its own, or that holds a symbol instance, an image, a placed file, type with an inline graphic or a raster effect, is still placed and evaluated again in every frame. At 1000 × 1000 pixels, a page of 2,000 instances of a symbol that holds an envelope takes 28 ms a frame instead of 126 ms, with the same pixels.