Format for reStructuredText syntax

Author: BastianZim

src/maintainer/knowledge_base.rst

@@ -866,7 +866,7 @@ Currently available packages:
 
 +-------------+-------------------+--------------+
 | Name        | Available on:     | Empty on:    |
-+-------------+-------------------+--------------+
++=============+===================+==============+
 | dataclasses | python >=3.6,<3.7 | python >=3.7 |
 +-------------+-------------------+--------------+
 | typing      |                   | python >=3   |