client: Add input tooltips, clear format, cleanup

client: Add input tooltips, clear format, cleanup

Add tooltips to all of the input widget items, improving
accessibility for otherwise icon-only buttons and menus.

Add button to clear formatting, making it easy to immediately remove
all those garish foreground and background colors you added, and the
italic/bold/underline, too.

Cleanup formatting options into distinct functions, paving the way
for external signals changing formatting.