Update README.md

Author: dminhhoang26

README.md

@@ -1,7 +1,7 @@
 ## [Github actions](https://github.com/actions)
 
 ## Note / Tip
-### Some css tips
+### Some html/css tips
 ```css
 
 awesome-class: {
@@ -76,6 +76,9 @@ Overflow text
 }
 ```
 
+
+Whitespace char: ` `
+
 ### Javascript
 - stopImmediatePropagation event
 - promise can add any value and return this value if not exec