Before adding any more features to todo_completion, I feel like I need test coverage, so this is a first stab at testing the completion results, via a new test function test_todo_completion.
Some basic tests showcase the capabilities.
Note: test-lib.sh now uses arrays, therefore all tests must use /bin/bash, not /bin/sh to avoid errors when sourcing test-lib. For consistency with todo.sh, we should have used Bash everywhere, anyway. Also note that t2000-multiline.sh needs some more quoting to avoid "Bash: ambiguous redirect" errors.
I.e. removed the colon after the ITEM#. Updated tasks are now listed like the 'todo.sh ls' command does, e.g.
42 smell the roses
This is in preparation to eventually use a function factored out from _list() for the verbose task output, which would enable coloring in the verbose message and thus align the verbose message output even more with the normal task output.
In verbose mode, commands first print the updated task, then summarize the change in the following line.
The add/addm/addto commands deviated from this, using "TODO: '<task>' added on line N."
This change splits this into two separate lines, obsoletes the implementation jargon of "line", and makes it easier to visually parse the message.
This is also a preparation for a possible future use of a _list()-like function, so that the updated task is processed and highlighted like the normal task output.
