Added Czech language support. Fixes #5170

docs/en_US/release_notes_4_19.rst

@@ -9,6 +9,7 @@ This release contains a number of bug fixes and new features since the release o
 New features
 ************
 
+| `Issue #5170 <https://redmine.postgresql.org/issues/5170>`_ -  Added Czech language support.
 
 Housekeeping
 ************

web/config.py

@@ -84,6 +84,7 @@ HELP_PATH = '../../../docs/en_US/_build/html/'
 LANGUAGES = {
     'en': 'English',
     'zh': 'Chinese (Simplified)',
+    'cs': 'Czech',
     'fr': 'French',
     'de': 'German',
     'it': 'Italian',