docs: add section about docs to contributing guide [skip ci]

CONTRIBUTING.md

@@ -55,6 +55,15 @@ General questions do not need to follow this checklist.
 Feel free to ask anything about using, developing or distributing Klogg. Such questions often
 help to improve project documentation.
 
+# Documentation
+
+Klogg has become a quite complex tool with many features. Any time spent fixing
+typos or clarifying sections in the documentation is greatly appreciated.
+Features that need better documentation can be found in this 
+[list](https://github.com/variar/klogg/issues?q=is%3Aissue+label%3A%22status%3A+need+documentation%22+). 
+Both open and closed issues marked with label `status: need documentation`
+require some work with documentation.
+
 # How to contribute code
 
 Unsure where to begin contributing to Klogg? 

README.md

@@ -18,6 +18,7 @@ Development status
 
 [![Next milestone](https://img.shields.io/github/milestones/progress-percent/variar/klogg/8?style=flat)](https://github.com/variar/klogg/milestone/8)
 [![Ready for testing](https://img.shields.io/github/issues-raw/variar/klogg/status:%20ready%20for%20testing?color=green&label=issues%20ready%20for%20testing&style=flat)](https://github.com/variar/klogg/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+ready+for+testing%22)
+[![Need documentation](https://img.shields.io/github/issues-search/variar/klogg?color=yellow&label=features%20need%20documentation&query=is%3Aissue%20label%3A%22status%3A%20need%20documentation%22&style=flat)](https://github.com/variar/klogg/issues?q=is%3Aissue+label%3A%22status%3A+need+documentation%22)
 [![GitHub commits](https://img.shields.io/github/commits-since/variar/klogg/v20.12.svg?style=flat)](https://github.com/variar/klogg/commits/)
 [![CI Build and Release](https://github.com/variar/klogg/actions/workflows/ci-build.yml/badge.svg)](https://github.com/variar/klogg/actions/workflows/ci-build.yml)