Update README.md

Hey there. As a Software Engineer who happens to be Nigerian, I think there are better ways of explaining a side effect than perpetuating stereotypes about a specific group of people. So I just made a small fix to make it more appropriate.

Author: iheanyi

README.md

@@ -529,7 +529,7 @@ function createFile(name) {
 A function produces a side effect if it does anything other than take a value in
 and return another value or values. A side effect could be writing to a file,
 modifying some global variable, or accidentally wiring all your money to a
-Nigerian prince.
+stranger.
 
 Now, you do need to have side effects in a program on occasion. Like the previous
 example, you might need to write to a file. What you want to do is to