docs: update Usage, update sample

Author: initdc

README.md

@@ -29,6 +29,14 @@ puts "s: #{s}"
 puts "n: #{n}"
 puts "r: #{r}"
 puts "e: #{e}"
+
+arr = [0, 1, 2]
+
+p arr[0]
+p Option.from(arr[0])
+p arr[10]?
+p Option.from?(arr[10]?)
+p Option.from! { arr[10] }
 ```
 
 ## Development

main.cr

@@ -1,4 +1,5 @@
 require "./src/option"
+# require "types/option"
 
 s = Some[0]
 n = None(Int32)[]
@@ -10,3 +11,11 @@ puts "s: #{s}"
 puts "n: #{n}"
 puts "r: #{r}"
 puts "e: #{e}"
+
+arr = [0, 1, 2]
+
+p arr[0]
+p Option.from(arr[0])
+p arr[10]?
+p Option.from?(arr[10]?)
+p Option.from! { arr[10] }