Remove the text written across the empty suggestion row #1218

#1210 removed the status line across the top of every panel, but the keyboard still writes a line across its suggestion row when there are no suggestions ("Prediction loading", "No suggestions", and so on). Remove it so nothing is written across the keyboard: the suggestion row keeps its reserved slots and stays blank until suggestions arrive. Messages that need attention keep floating beside the panel as they do now.

Update the docs site keyboard page, which says the empty suggestion row still says why.