templates: add filter to reverse list The filter supports only lists because for lists, it’s straightforward to implement. Reversing text doesn’t seem very useful and is hard to implement. Reversing the bytes would break multi-bytes encodings. Reversing the code points would break characters consisting of multiple code points. Reversing graphemes is non-trivial without using a library not included in the standard library.

Ancestors of 5
4 2 0 
Ancestors of 6 and 5
4 3 2 1 0 
Ancestors of 5 and 4
4 2 0 
Ancestors of 7, stop at 6
6 
Ancestors of 7, including revs
7 6 5 4 3 2 1 0 
Ancestors of 7, 5 and 3, including revs
7 6 5 4 3 2 1 0 

Descendants of 5
7 8 
Descendants of 5 and 3
6 7 8 
Descendants of 5 and 4
5 7 8