fix(variables1): Correct wrong word in comment

Author: ckeschnat

exercises/variables/variables1.rs

@@ -4,7 +4,7 @@
 // About this `I AM NOT DONE` thing:
 // We sometimes encourage you to keep trying things on a given exercise,
 // even after you already figured it out. If you got everything working and
-// feel ready for the next exercise, you the `I AM NOT DONE` comment below.
+// feel ready for the next exercise, remove the `I AM NOT DONE` comment below.
 
 // I AM NOT DONE