Remove inaccurate guidance about doc filters being removed in 3.0 (re…

…moved in 2.0 instead). (#916)

changelog.txt

@@ -147,7 +147,7 @@ Changed
 Deprecated
 ++++++++++
 
- - ``doc_filter`` arguments, which are replaced by namespaced filters. Due to their long history, ``doc_filter`` arguments will still be accepted in signac 2.0 and will only be removed in 3.0 (#516).
+ - ``doc_filter`` arguments, which are replaced by namespaced filters.
  - The modules ``signac.core.attrdict``, ``signac.core.json``, ``signac.core.jsondict``, and ``signac.core.synceddict.py`` are deprecated in favor of the new ``SyncedCollection`` classes and will be removed in signac 2.0 (#483).
 
 Fixed