Added reverse op

pkg/yqlib/doc/operators/sort.md

@@ -2,8 +2,11 @@
 
 Sorts an array. Use `sort` to sort an array as is, or `sort_by(exp)` to sort by a particular expression (e.g. subfield).
 
+To sort by descending order, pipe the results through the `reverse` operator after sorting.
+
 Note that at this stage, `yq` only sorts scalar fields.
 
+
 {% hint style="warning" %}
 Note that versions prior to 4.18 require the 'eval/e' command to be specified. 
 
@@ -28,6 +31,26 @@ will output
 - a: cat
 ```
 
+## Sort descending by string field
+Use sort with reverse to sort in descending order.
+
+Given a sample.yml file of:
+```yaml
+- a: banana
+- a: cat
+- a: apple
+```
+then
+```bash
+yq 'sort_by(.a) | reverse' sample.yml
+```
+will output
+```yaml
+- a: cat
+- a: banana
+- a: apple
+```
+
 ## Sort array in place
 Given a sample.yml file of:
 ```yaml