Fixes a typo in comment for the type conversion and lucky-numbers example. (#1691)

Author: diegodesouza

concepts/type-conversion/about.md

@@ -161,7 +161,7 @@ When a value is used in a boolean context, JavaScript will apply the same rules
   ```javascript
   const num = 0;
   if (num) {
-    // this block NOT is executed because 0 is falsy
+    // this block is NOT executed because 0 is falsy
   }
 
   const name = 'Jin';

concepts/type-conversion/introduction.md

@@ -107,7 +107,7 @@ Coercion to boolean commonly occurs for
 ```javascript
 const num = 0;
 if (num) {
-  // this block NOT is executed because 0 is falsy
+  // this block is NOT executed because 0 is falsy
 }
 ```
 

exercises/concept/lucky-numbers/.docs/introduction.md

@@ -107,7 +107,7 @@ Coercion to boolean commonly occurs for
 ```javascript
 const num = 0;
 if (num) {
-  // this block NOT is executed because 0 is falsy
+  // this block is NOT executed because 0 is falsy
 }
 ```