Make special characters visible

Output '_', '^', '{', '}' and '\' characters with the 'text' command

Make '_', '^', '{', '}' and '\' characters visible for the 'tex' interpreter (Put '\' in front).
With that function, you change the text 'y = x^2', where the letter 2 is superscript using a 'tex' interpreter, to 'y = x\^2', where the text appears as written before ('y = x^2').