Update for pattern comprehensions (#1504)

- nested
- named path

Co-authored-by: Matea Pesic <80577904+matea16@users.noreply.github.com>

Author: Ignition

pages/querying/expressions.mdx

@@ -243,6 +243,10 @@ RETURN actor.name, years, titles;
 ```
 The whole predicate, including the `WHERE` keyword, is optional and may be omitted.
 
+Pattern comprehensions can be nested, for example `[(n)-->(m) | [(m)-->(x) | x.id]]` returns a list of lists.
+
+You can also bind the matched path to a variable using the syntax `[path = (a)-[r]->(b) | length(path)]`.
+
 ### Pattern comprehension in `WHERE` clause
 
 Pattern comprehension can also be combined with comprehension constructs inside the `WHERE` clause.