Tweak coverage configuration for type checking (jaraco/skeleton#97)

* Tweak coverage configuration for type checking

* Use `exclude_also` instead of `exclude_lines`

Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>

* Add reference to the issue.

---------

Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>
Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

Author: 3 people

.coveragerc

@@ -7,3 +7,7 @@ disable_warnings =
 
 [report]
 show_missing = True
+exclude_also =
+	# jaraco/skeleton#97
+	@overload
+	if TYPE_CHECKING: