Improve LogStreamerInput docs

Author: sathieu

docs/source/config/inputs/logstreamer.rst

@@ -53,6 +53,7 @@ Config:
     When using multiple logstreams, the differentiator is a set of strings that
     will be used in the naming of the logger, and portions that match a captured
     group from the ``file_match`` will have their matched value substituted in.
+    Only the last (according to priority) file per differentiator is kept opened.
 - translation (hash map of hash maps of ints):
     A set of translation mappings for matched groupings to the ints to use for
     sorting purposes.