Patch tested by compiling with `__attribute__ ((format (printf, 2, 3)))`
applied to `cmd_results_new`.
String usage constants have been converted from pointers to arrays when
encountered. General handler format strings were sometimes modified to
include the old input string, especially for unknown command errors.
In the conversion to `parse_boolean` for `cmd_ws_auto_back_and_forth`,
the `negation` was never removed causing the setting to be the opposite
of what it should be.