docs: add information to avoid misunderstanding (#1619)

Co-authored-by: Divyansh Singh <40380293+brc-dd@users.noreply.github.com>

docs/guide/markdown.md

@@ -387,6 +387,8 @@ Additionally, you can define a number of lines to focus using `// [!code focus:<
 
 **Input**
 
+Note that only one space is required after `!code`, here are two to prevent processing.
+
 ````
 ```js
 export default {
@@ -417,6 +419,8 @@ Adding the `// [!code --]` or `// [!code ++]` comments on a line will create a d
 
 **Input**
 
+Note that only one space is required after `!code`, here are two to prevent processing.
+
 ````
 ```js
 export default {
@@ -449,6 +453,8 @@ Adding the `// [!code warning]` or `// [!code error]` comments on a line will co
 
 **Input**
 
+Note that only one space is required after `!code`, here are two to prevent processing.
+
 ````
 ```js
 export default {