Add missing method to _ManHelpFormatter (#5577)

Co-authored-by: Daniël van Noord <[email protected]>

Author: Pierre-Sassoulas

pylint/config/man_help_formatter.py

@@ -6,7 +6,6 @@
 import time
 
 
-# pylint: disable=abstract-method; by design?
 class _ManHelpFormatter(optparse.HelpFormatter):
     def __init__(
         self, indent_increment=0, max_help_position=24, width=79, short_first=0
@@ -107,6 +106,10 @@ def format_tail(pkginfo):
 """
         return tail
 
+    def format_usage(self, usage):
+        """Taken from optparse.IndentedHelpFormatter"""
+        return f"Usage: {usage}\n"
+
 
 def _generate_manpage(optparser, pkginfo, section=1, stream=sys.stdout, level=0):
     formatter = _ManHelpFormatter()