Merge pull request #980 from BretHudson/2.0-fix-glsl-for-loop

[beta.p5js.org] Typo: Switch "let" to "int" to make GLSL code valid

Author: davepagurek

src/content/tutorials/en/intro-to-glsl.mdx

@@ -287,7 +287,7 @@ int maxVal = 10;
 if (something) {
   maxVal = 20;
 }
-for (let i = 0; i < 20; i++) {
+for (int i = 0; i < 20; i++) {
   if (i == maxVal) {
     break;
   }