Clean up unused variables and remove redundant map() in standard library modules

[evdakim1234]

A static analysis tool (svace) reported several minor issues in Python's standard library modules.
In Lib/_markupbase.py;
Lib/_markupbase.py;
Lib/_markupbase.py;
Lib/idlelib/multicall.py;
Lib/idlelib/multicall.py;
Lib/turtle.py.
Unused variables that can be replaced with _

In Lib/idlelib/searchengine.py
Removal of an unused/redundant map() function call.

[gvanrossum]

See the PR for why I am closing this.