docs: add task list example (#1153)

Author: mcanouil

docs/authoring/markdown-basics.qmd

@@ -130,7 +130,11 @@ This document provides examples of the most commonly used markdown syntax. See t
 |     i) sub-item 1                 |      i) sub-item 1              |
 |          A.  sub-sub-item 1       |           A.  sub-sub-item 1    |
 | ```                               |                                 |
-|                                   |                                 |
++-----------------------------------+---------------------------------+
+| ``` markdown                      |                                 |
+| - [ ] Task 1                      | - [ ] Task 1                    |
+| - [x] Task 2                      | - [x] Task 2                    |
+| ```                               |                                 |
 +-----------------------------------+---------------------------------+
 | ``` markdown                      |                                 |
 | (@)  A list whose numbering       |  (1) A list whose numbering     |