docs: make the users.sort example directly runnable

doc/docs.md

@@ -614,7 +614,7 @@ numbers.sort(a > b) // 3, 2, 1
 
 ```v
 struct User { age int  name string }
-mut users := [...]
+mut users := [User{21, 'Bob'}, User{20, 'Zarkon'}, User{25, 'Alice'}]
 users.sort(a.age < b.age)   // sort by User.age int field
 users.sort(a.name > b.name) // reverse sort by User.name string field
 ```