Put logic for `parse_fun_call()` in a comment.

src/parse/parse.rs

@@ -31,3 +31,9 @@ pub fn parse_var_declaration(mut tokens: Lexer<Token>) -> Option<Expr> {
     }
     tok
 }
+
+pub fn parse_fun_call(mut tokens: Lexer<Token>) -> Option<Expr> {
+    // Is it an Ident? -> Is it a LeftParen? -> Is it a value (I should really make a function to parse that) or is it a RightParen?
+    //                                                ↓                      						      ↓
+    //                              If it's a value, push that to `params`.				 Otherwise, params will just be a `Vec::new()`.
+}