docs: Add instructions on how to view the coverage webpage

docs/coverage.md

@@ -7,4 +7,18 @@ This will generate a webpage `coverage/index.html` with a listing of all the sou
 
 ![Index.html screenshot](./coverage_example.png)
 
-It can also be used automatically on all test files by running `./test.sh coverage`.
+It can also be used automatically on all test files by running `./test.sh coverage`.
+
+## Viewing the coverage webpage
+
+You can view the webpage in your browser by navigating to the coverage directory and running the following command:
+
+```python3 -m http.server```
+
+For example:
+
+```console
+user@host:/workspaces/langproc-cw# cd coverage
+user@host:/workspaces/langproc-cw/coverage# python3 -m http.server
+Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
+```