chore(web): Update test keyboard

Add two longpress menus to the `diacritic_rota` keyboard:

- longpress on <kbd>1</kbd>: one subkey that is too wide to fit in the
  osk. Keyman is expected to resize the key so that it does fit.
- longpress on <kbd>2</kbd>: Subkeys for A-Z. Subkeys B and Y are
  double wide. The keys are expected to be displayed in multiple rows
  so that each row fits within the width. Note that there are too many
  keys so that the rows don't fit vertically.

Already existing is the longpress on <kbd>.</kbd>. Since the base
keys are wider they won't fit in one row. Keyman is expected to display
them in two rows.

web/src/test/manual/web/keyboards/diacritic_rota/README.md

@@ -5,7 +5,18 @@ Version 1.0
 
 Description
 -----------
-Diacritic Rota generated from template
+
+Diacritic Rota keyboard used for testing multitap and longpress.
+
+- longpress on <kbd>1</kbd>: one subkey that is too wide to fit in the
+  osk. Keyman is expected to resize the key so that it does fit.
+- longpress on <kbd>2</kbd>: Subkeys for A-Z. Subkeys B and Y are
+  double wide. The keys are expected to be displayed in multiple rows
+  so that each row fits within the width. Note that there are too many
+  keys so that the rows don't fit vertically.
+- longpress on <kbd>.</kbd>: 8 subkeys which won't fit in one row
+  because the base keys are wider. Keyman is expected to display them
+  in two rows.
 
 Links
 -----