docs: moved streams

Author: NickSdot

docs-old/streams.md docs/source/core/streams/index.mddocs-old/streams.md renamed to docs/source/core/streams/index.md

@@ -17,6 +17,7 @@ hidden: true
 core/data-structures/index
 core/memory-management/index
 core/output-buffering
+core/streams/index
 ```
 
 ```{toctree}