Recommended and mentioned products
The Kate Editor Homepage
A free source code editor which supports several programming languages running under the MS Windows environment.
Notepad++ has recently added dark mode (if you need a text editor and not an entire IDE).
A modified version (fork) of Notepad2 based on Kai Liu's and other people's patches.
I've been using Notepad2-mod as my default text editor for a very long time. It has syntax highlighting for many languages and many other features.