Update index.md (#30085)
Update index.md (#30085)

Removed an unnecessary example as well as changed the description for the usage of the 'await' keyword. Also added an example for async method declarations.
jonathanihm/freeCodeCamp,BhaveshSGupta/FreeCodeCamp,raisedadead/FreeCodeCamp,FreeCodeCamp/FreeCodeCamp,FreeCodeCamp/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,BhaveshSGupta/FreeCodeCamp,jonathanihm/freeCodeCamp,raisedadead/FreeCodeCamp