Adding our Ctrl+A/E/H/U/W actions alongside Kate's own (Select All, Close,
lowercase, …) left both claiming the same sequence, so Qt reported ambiguous
shortcuts. clearConflictingShortcuts() now walks every GUI-client action
collection and removes our sequences from any foreign action, also clearing
their KActionCollection default shortcuts so they are not restored. The sweep
runs at setup, once more deferred to the event loop (after the GUI factory
merges all clients), and on every viewCreated so new documents don't
re-introduce the conflict.
Also implements the five Acme motions against the View/Document API with
semantics ported from plan9port acme text.c. All 5 ctest suites green.
1b56cca1a2