doc: make theme consistent across api and other docs

Since website based on 2 different repos, there was an inconsistency in theme selection, so we had 2 independant theme props. Now only one stored in local storage is a single source of truth PR-URL: #50877 Reviewed-By: Claudio Wunder <[email protected]> Reviewed-By: Yagiz Nizipli <[email protected]>

Author: demakoff

BUILDING.md

@@ -462,6 +462,12 @@ make docopen
 This will open a file URL to a one-page version of all the browsable HTML
 documents using the default browser.
 
+```bash
+make docclean
+```
+
+This will clean previously built doc.
+
 To test if Node.js was built correctly:
 
 ```bash

doc/api_assets/api.js

@@ -2,11 +2,11 @@
 
 {
 functionsetupTheme(){
-constkCustomPreference='customDarkTheme';
-constuserSettings=sessionStorage.getItem(kCustomPreference);
+conststoredTheme=localStorage.getItem('theme');
 constthemeToggleButton=document.getElementById('theme-toggle-btn');
 
-if(userSettings===null&&window.matchMedia){
+// Follow operating system theme preference
+if(storedTheme===null&&window.matchMedia){
 constmq=window.matchMedia('(prefers-color-scheme: dark)');
 
 if('onchange'inmq){
@@ -28,16 +28,16 @@
 if(mq.matches){
 document.documentElement.classList.add('dark-mode');
 }
-}elseif(userSettings==='true'){
+}elseif(storedTheme==='dark'){
 document.documentElement.classList.add('dark-mode');
 }
 
 if(themeToggleButton){
 themeToggleButton.hidden=false;
 themeToggleButton.addEventListener('click',function(){
-sessionStorage.setItem(
-kCustomPreference,
-document.documentElement.classList.toggle('dark-mode'),
+localStorage.setItem(
+'theme',
+document.documentElement.classList.toggle('dark-mode') ? 'dark' : 'light',
 );
 });
 }

doc/contributing/collaborator-guide.md

@@ -532,9 +532,10 @@ The TSC serves as the final arbiter where required.
 [build](https://github.com/nodejs/build/issues) repositories, open new
  issues. Run a new CI any time someone pushes new code to the pull request.
 4. Check that the commit message adheres to [commit message guidelines][].
-5. Add all necessary [metadata](#metadata) to commit messages before landing. If
- you are unsure exactly how to format the commit messages, use the commit log
- as a reference. See [this commit][commit-example] as an example.
+5. Add all necessary [metadata][git-node-metadata] to commit messages before
+ landing. If you are unsure exactly how to format the commit messages, use
+ the commit log as a reference. See [this commit][commit-example] as an
+ example.
 
 For pull requests from first-time contributors, be
 [welcoming](#welcoming-first-time-contributors). Also, verify that their git