Added XML decoder (#1044)

pkg/yqlib/doc/operators/collect-into-array.md

@@ -0,0 +1,41 @@
+# Collect into Array
+
+This creates an array using the expression between the square brackets.
+
+
+## Collect empty
+Running
+```bash
+yq eval --null-input '[]'
+```
+will output
+```yaml
+[]
+```
+
+## Collect single
+Running
+```bash
+yq eval --null-input '["cat"]'
+```
+will output
+```yaml
+- cat
+```
+
+## Collect many
+Given a sample.yml file of:
+```yaml
+a: cat
+b: dog
+```
+then
+```bash
+yq eval '[.a, .b]' sample.yml
+```
+will output
+```yaml
+- cat
+- dog
+```
+