docs: fix missing tag end in clipboard example (#32695)

Co-authored-by: Paul Hollinsky <[email protected]>

docs/api/clipboard.md

@@ -76,7 +76,7 @@ Writes `markup` to the clipboard.
 ```js
 const { clipboard } = require('electron')
 
-clipboard.writeHTML('<b>Hi</b')
+clipboard.writeHTML('<b>Hi</b>')
 ```
 
 ### `clipboard.readImage([type])`