Update json-columns.cs (#343)

Added missing indentation and removed extraneous semicolon

Author: alexkeh

samples/ef-core/json/json-columns.cs

@@ -49,7 +49,7 @@ public class AuthorContext : DbContext
  protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
  {
  optionsBuilder.UseOracle("User Id=<USER>; Password=<PASSWORD>; Data Source=<DATA SOURCE>"
- , b => b.UseOracleSQLCompatibility(OracleSQLCompatibility.DatabaseVersion21)); ;
+ , b => b.UseOracleSQLCompatibility(OracleSQLCompatibility.DatabaseVersion21));
  }
 
  protected override void OnModelCreating(ModelBuilder modelBuilder)
@@ -76,8 +76,8 @@ public static void Main()
  Name = "John Smith",
  Contact = new ContactDetails()
  {
- Phone = "555 123 4567",
- Address = new Address("1 Any Street", "Austin", "78741", "US")
+  Phone = "555 123 4567",
+  Address = new Address("1 Any Street", "Austin", "78741", "US")
  }
  };