fix: fix typo in examples

exl/00_variables.fzs

@@ -5,7 +5,7 @@ str someString = "world, hello!";
 // 2. Change variable value:
 someString = "hello, world!";
 
-// Variables helps you store values to use it later
+// Variables help you store values to use it later
 int a = 2;
 int b = a + a * a;
 int c = a * b;
@@ -13,7 +13,7 @@ int c = a * b;
 printline("Now we got 12:");
 printline(c);
 
-// Also, there is many different types to help your program
+// Also, there are many different variable types to help your program
 //  work with many things:
 int signedInteger;
 uint unsignedInteger;