Feature request error on unrecognized linkcheckerrc settings

[pacenathan]

Summary

If I put a setting in the wrong category, or spell it wrong, or if linkchecker has a bug where it doesn't actually recognize documented settings, I get no warning - it just runs as if everything is fine, but fails to do what I thought I told it to do.

Steps to reproduce

1. Put e.g. ignore=foo in the [checking] section
2. Put resultcachesize=100 anywhere, before PR Fix bug where resultscachesize setting was ignored #659
3. Accidentally spell maxnumurls as maxurls

...then run linkchecker. It will run and not complain.

Actual result

It runs and doesn't obey the config setting I thought I set, and doesn't complain or help me identify the problem.

Expected result

It errors and tells me about the unexpected config value.

Environment

• Operating system: Darwin 21.6.0 Darwin Kernel Version 21.6.0: Wed Aug 10 14:28:23 PDT 2022; root:xnu-8020.141.5~2/RELEASE_ARM64_T6000 arm64
• Linkchecker version: LinkChecker 10.1.0.post66+ge4d65155.d20220908180221 released 2022-09-06
• Python version: Python 3.9.13
• Install method: Install from local source

Configuration file

One example:

[checking]
threads=10
maxrequestspersecond=10000
# anchorcachesize=0
ignore=foo

[filtering]
checkextern=1

[output]
fileoutput=html
# log=text
log=none
# log=csv
# debug=plugin

[AnchorCheck]

Logs

linkchecker --config ~/temp/linkchecker.rc http://127.0.0.1:8000/

Other notes