Select All takes the whole document's text while scrolling continuously (#2639)

Scrolling continuously, Edit > Select All (Cmd+A) selects the text of
every page of the document; one page at a time it still selects the page
shown, as does a document of one page. Shown pages highlight as their
text arrives, and Copy gets all of it in page order, reading the text of
pages not read for display (text far away is let go to bound memory, so
it isn't kept for this). A press on a page or Escape ends it. Select All
still returns whether text is selected.

The Select All parity entry covers both modes; the viewer and copy
security tests run one page at a time, which is what they check.

parity/acrobat-features.toml

@@ -1543,15 +1543,15 @@ notes = "Keyboard, Edit-menu, page-context-menu and floating-selection Copy hono
 
 [[feature]]
 id = "view.select-all"
-title = "Select all text on a page"
+title = "Select all text"
 area = "B"
 tier = "P1"
 milestone = "M3"
 status = "shipped"
 commands = []
 tools = []
-evidence = ["crates/ui-egui/tests/viewer.rs::view_history_select_all_and_find_options"]
-notes = "⌘A on the current page"
+evidence = ["crates/ui-egui/tests/viewer.rs::view_history_select_all_and_find_options", "crates/ui-egui/src/canvas.rs::select_all_copies_the_whole_document_while_scrolling_continuously", "crates/ui-egui/src/canvas.rs::select_all_of_the_document_only_while_scrolling_through_several_pages"]
+notes = "⌘A: the current page one page at a time; the whole document scrolling continuously (#2639), copied whole"
 
 [[feature]]
 id = "view.copy-with-layout"