cgen: fix match for one branch (#9234)

vlib/v/gen/c/cgen.v

@@ -3810,7 +3810,7 @@ fn (mut g Gen) match_expr_classic(node ast.MatchExpr, is_expr bool, cond_var str
 			}
 		}
 		g.stmts_with_tmp_var(branch.stmts, tmp_var)
-		if g.inside_ternary == 0 && node.branches.len > 1 {
+		if g.inside_ternary == 0 && node.branches.len >= 1 {
 			g.write('}')
 		}
 	}

vlib/v/tests/match_expr_with_one_branch_test.v

@@ -0,0 +1,12 @@
+enum Color {
+	red
+}
+
+fn test_match_one_branch() {
+	col := Color.red
+	match col {
+		.red {
+			assert true
+		}
+	}
+}