docs ecosystem/integrations update 4 (#5590)

# docs `ecosystem/integrations` update 4

Added missed integrations. Fixed inconsistencies. 

## Who can review?

@hwchase17 
@dev2049

docs/integrations/roam.md

@@ -0,0 +1,17 @@
+# Roam
+
+>[ROAM](https://roamresearch.com/) is a note-taking tool for networked thought, designed to create a personal knowledge base.
+ 
+## Installation and Setup
+
+There isn't any special setup for it.
+
+
+
+## Document Loader
+
+See a [usage example](../modules/indexes/document_loaders/examples/roam.ipynb).
+
+```python
+from langchain.document_loaders import RoamLoader
+```