fmt: process `defer` statement

vlib/v/fmt/fmt.v

@@ -138,6 +138,11 @@ fn (f mut Fmt) stmt(node ast.Stmt) {
 			f.indent--
 			f.writeln(')\n')
 		}
+		ast.DeferStmt {
+			f.writeln('defer {')
+			f.stmts(it.stmts)
+			f.writeln('}')
+		}
 		ast.ExprStmt {
 			f.expr(it.expr)
 			if !f.single_line_if {

vlib/v/fmt/tests/simple_expected.vv

@@ -83,6 +83,12 @@ fn get_user_ptr() &User {
 	return &User{}
 }
 
+fn fn_with_defer() {
+	defer {
+		close()
+	}
+}
+
 struct Foo {
 	field1        int
 	field2        string

vlib/v/fmt/tests/simple_input.vv

@@ -88,6 +88,11 @@ fn get_user_ptr() & User {
 	return &User{}
 }
 
+fn fn_with_defer() {
+defer {	close()
+}
+}
+
 struct Foo {
 	field1 int
 	field2 string