Merge PR #1068: Table › Convert Rows › To Header, To Body and To Footer

crates/engine/src/cmd/table.rs: add the PR's three commands before the branch's select commands, which keep their target descriptions (#803).
docs/gaps.md: keep the branch's text; Convert Rows leaves the list of missing menu items.

docs/gaps.md

@@ -136,8 +136,8 @@ Kind: **F** feature · **U** UI/UX · **T** typography · **FF** file format ·
 
 ### 12. Tables in depth (F)
 - **Missing:** anchored objects in cells not drawn (#163); Table ▸ Table Options and Cell Options
-  submenus as InDesign lays them out, Diagonal Lines, Convert Rows to Header/Body/Footer, Edit
-  Header/Footer, Go to Row; general reliability (#20).
+  submenus as InDesign lays them out, Diagonal Lines, Edit Header/Footer,
+  Go to Row; general reliability (#20).
 - **Estimate:** 25–40 h.
 
 ### 13. Hyphenation and spelling languages (T, L)
@@ -170,7 +170,7 @@ Kind: **F** feature · **U** UI/UX · **T** typography · **FF** file format ·
   Window ▸ Arrange (2-up … 6-up), Trap Presets, Overlays, Edit ▸ Assign Profiles / Convert to
   Profile / Edit Original, File ▸ File Info / Open PDF / Document and Print Presets / User
   Settings, Type ▸ Size presets, Table ▸ Table Options / Cell Options submenus, Paste Before/After,
-  Convert Rows/Columns, Object ▸ Interactive ▸ Convert to (form fields),
+  Convert Columns, Object ▸ Interactive ▸ Convert to (form fields),
   View ▸ Extras badges and Story Editor options. Pages panel ▸ Parent Options (Based on Parent is
   the `layout.parents.options` command only); overriding a base parent's items on a parent spread
   itself (overrides work on document pages only).