Notepad++ is a fantastic tool that I use for hours every day, but it's not ideal for editing large Sysmon config files, I recently looked at other options and found a setup that I was happy with - let's take a look at how you can replicate this.
Now save your config file and give it a name, make sure to save it to the folder where you initialized your Git repo, in my case C:\Repos\sysmon-config
You should see a "1" icon next to the source control menu option in VS Code after saving your config file. Navigate to that menu, add your commit message, stage the changes and then commit them to your GitHub repo:
Now your Sysmon config is source controlled and resides in a feature-rich text editor with auto-complete unique to Sysmon's config syntax, nice!
As a final step, use the Bookmarks add-on to configure bookmarks within your Sysmon config so you can follow along with the various sections in a large config file.
If you've installed the bookmarks extension, navigate to the line where you want to set your bookmark and hit CTRL+ALT+K (Or right click --> toggle bookmark), in my case I'm going to bookmark my ProcessCreate exclusions section: