Update docs/source/filters.rst

Co-authored-by: Thomas Perl <[email protected]>

docs/source/filters.rst

@@ -530,7 +530,7 @@ If ``repl`` is not specified, the full match will be included in the output.
    url: https://example.com/regex-findall.html
    filter:
        - re.findall:
-           pattern: 'The next draw is on (\d\d\d\d-\d\d-\d\d).'
+           pattern: 'The next draw is on (\d{4}-\d{2}-\d{2}).'
            repl: '\1'
        - re.findall: '[0-9]+'