Textedit "make plain text" still retains fancy single quotes

I'm trying to do what I used to regularly do with notepad on Windows, copy a bunch of text from another program into Notepad so I could lose the text formatting, then copy into a code editor or other program as plain text.

TextEdit claims to have a option to lose the formatting, but it doesn't work completely as the single quotes around a 'word' are still the fancy ones, i.e. open-quote and close-quote. Even if I delete the quoted word completely and type in from scratch, textedit still automatically converts my plain single quotes into the fancy ones as soon as it realizes that I am surrounding a word with the quotes.

What program can I use to get the fancy quotes to disappear and just show the plan single quote that code compilers understand?

Thanks. John