Translate 'Uncheck all ToDos'

'Uncheck all ToDos' button isn't translated for another languages.

Breaking Change: inverted meaning of "*" and "!" in due/start-at/before/after. Makes more sense that way and was not documented before.

remove further searchpattern references and (probably) defunct code.

added option to set priority for to-do item:
! - low priority
!! - medium priority
!!! - high priority

more than 3 exclamation marks are parsed as high priority
it simply adds class name to <span

added option to set priority for to-do item:
! - low priority
!! - medium priority
!!! - high priority

more than 3 exclamation marks are parsed as high priority
it simply adds class name to <span class="todotext">...

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Updated function documentation

Improves handling of uncheck all button

Adds button to reset all ToDos on the page

Wraps every todo in a span of class 'todo'

default for $data['username']

is_object -> isset

fix 'Unknown key' for PHP8.2

fix 'Unknown key' for PHP8.2

Shows empty todo items in todo list as <no title>

Allows empty todo items

Refactores rendering code to properly use the render data

- Removes $todotitle as it is not used
- Skips rendering if $data is empty

Initialise $result for all paths

Fixes undefined variable $return in todo.php on line 284

Fixes undefined variable $condition2 in list.php on line 419

return empty array if there are no todo pages

Calling function expects an array.
Returning an empty array instead of null saves a null check and also makes sense when reasoning about the function.

Update todo.php

Update todo.php

Ensure `$option` is not empty before unpacking

Fix for empty $todopages when array is expected.

Fixes #139. related to #121.
Fixes same problem in other functions too.

fix shortlist because of unnecessary return

#128

Don't try to render empty Todotable. Fixes #121

added display of user and date of task completion.