Document known conventions for key:value

[clach04]

similar to todotxt/todo.txt#8
Potentially related todotxt/todo.txt#79

Also see todo.txt clients and tags google sheet

From spec

Current spec mentions two ideas/suggestions/conventions for key value:

• pri
  • Example; pri:A - List of "Special tag / Additional Definitions" todotxt/todo.txt#8 (comment)
• due
  • Example; due:2010-01-02
  • due:YYYY-MM-DD to represent the due date

Seen in the wild

• t:YYYY-MM-DD Start/threshold date - List of "Special tag / Additional Definitions" todotxt/todo.txt#8 (comment) and List of "Special tag / Additional Definitions" todotxt/todo.txt#8 (comment)
  • The t tag gives a start date to an item (also called a threshold, hence the t). It's another way of filtering.
• issue - List of "Special tag / Additional Definitions" todotxt/todo.txt#8 (comment)
• comp - completion progress - List of "Special tag / Additional Definitions" todotxt/todo.txt#8 (comment)
• • Recurrence - List of "Special tag / Additional Definitions" todotxt/todo.txt#8 (comment)
• rec Recurrence with rec:\+?[0-9]+[dwmyb] as described here and here but with a twist.
  • By default Simpletask will use the date of completion for recurring as described in the link. However if the rec includes a plus (e.g. rec:+2w), the date is determined from the original due or threshold date..
  • rec:1b will recur after 1 weekday (mnemonic business-day).
  • The format is described by a regular expression, so in words the syntax is rec: followed by an optional + then 1 or more numbers and then followed by one of day, week, month or year. For example rec:12d sets up a 12 day recurring task.
  • Android SimpleTask, from https://github.com/mpcjanssen/simpletask-android/blob/master/app/src/main/assets/index.en.md#extensions (as of 2022-09-11):
• Hidden tasks with the specified tag h:1, this allows dummy tasks with predefined lists and tags so that lists and tags will be available even if the last task with the tag/list is removed from todo.txt. These tasks will not be shown by default. You can temporarily display them from the Settings. also see hide
  • seen in SimpleTask
• uuid - also see id
  • seen in SimpleTask
• id - https://gitter.im/todotxt/Lobby?at=6284470aeaf3267f8566d9e3
• blocks - https://gitter.im/todotxt/Lobby?at=6284470aeaf3267f8566d9e3
• wait - Hide until wait date, essentially an expected start date - https://lwn.net/Articles/824608/

TODO copy/paste my comments here. Then either new (linked) file or include in spec.