Update contributing guide

Author: hynek

.github/CONTRIBUTING.md

@@ -98,14 +98,20 @@ $ tox run -e docs-watch
 
 This will build the documentation, watch for changes, and rebuild it whenever you save a file.
 
-To just build the documentation and run doctests, use:
+To just build the documentation and exit immediately use:
 
 ```console
-$ tox run -e docs
+$ tox run -e docs-build
 ```
 
 You will find the built documentation in `docs/_build/html`.
 
+To run doctests:
+
+```console
+$ tox run -e docs-doctests
+```
+
 
 ## Code
 

.github/workflows/ci.yml

@@ -172,7 +172,7 @@ jobs:
         if: ${{ failure() }}
 
   docs:
-    name: Run doctests
+    name: Run doctests & render changelog
     runs-on: ubuntu-latest
     needs: build-package
     steps: