docs: use local link in docs to reference itself & missing CPU config (#1704)

* docs: use local link in docs to reference itself

* also fix missing cpu config docs

docs/content/contribution/documentation.md

@@ -12,7 +12,7 @@ There are a few areas where documentation changes are often needed:
 
 - The [`README.md`](https://github.com/ClementTsang/bottom/blob/main/README.md)
 - The help menu inside of the application (located [here](https://github.com/ClementTsang/bottom/blob/main/src/constants.rs))
-- The [extended documentation](https://clementtsang.github.io/bottom/nightly/) (here)
+- The [extended documentation](../index.md) (what you're reading right now)
 - The [`CHANGELOG.md`](https://github.com/ClementTsang/bottom/blob/main/CHANGELOG.md)
 
 ## How should I add/update documentation?

docs/mkdocs.yml

@@ -166,11 +166,12 @@ nav:
       - "Command-line Options": configuration/command-line-options.md
       - "Config File":
           - configuration/config-file/index.md
-          - "Flags": configuration/config-file/flags.md
-          - "Styling": configuration/config-file/styling.md
-          - "Layout": configuration/config-file/layout.md
+          - "CPU Widget": configuration/config-file/cpu.md
           - "Data Filtering": configuration/config-file/data-filtering.md
-          - "Processes": configuration/config-file/processes.md
+          - "Flags": configuration/config-file/flags.md
+          - "Layout": configuration/config-file/layout.md
+          - "Processes Widget": configuration/config-file/processes.md
+          - "Styling": configuration/config-file/styling.md
   - "Contribution":
       - "Issues, Pull Requests, and Discussions": contribution/issues-and-pull-requests.md
       - "Documentation": contribution/documentation.md