You see just because you can work in a plain text editor and it is useful from time to time, doesn't mean you have to and you probably won't want to. Because with a basic text editor you're completely on your own writing the stuff and there are other applications that can actually help you write this code and make your life easier. First we have programmer's text editors. These are plain text editors with some extra features added on and there are many of them available on every platform. Some are free and some are commercial.
The singular forum, I presume, would be a programmer's text editor. And as far as I can see, even though the word programmer grammatically is in the possessive case, it doesn't really express possession. But rather it is used an an adjective to describe the compound noun text editor. And when we say a programmer's text editor, we don't mean that this is a text editor that belongs to somebody whose trade is computer programming, but rather when we say that we're really asking the following question: what kind of text editor is this? The answer is: programmer's or a programmer's one. Is my line of reasoning valid? Do you think I understand this type of grammar fine?