zig fmt: Preserve trailing comma after single-item switch case

lib/std/zig/parser_test.zig

@@ -2230,6 +2230,10 @@ test "zig fmt: switch cases trailing comma" {
         \\        1,2,3 => {},
         \\        4,5, => {},
         \\        6... 8, => {},
+        \\        9 ...
+        \\        10 => {},
+        \\        11 => {},
+        \\        12, => {},
         \\        else => {},
         \\    }
         \\}
@@ -2240,7 +2244,12 @@ test "zig fmt: switch cases trailing comma" {
         \\        4,
         \\        5,
         \\        => {},
-        \\        6...8 => {},
+        \\        6...8,
+        \\        => {},
+        \\        9...10 => {},
+        \\        11 => {},
+        \\        12,
+        \\        => {},
         \\        else => {},
         \\    }
         \\}

lib/std/zig/render.zig

@@ -1894,9 +1894,6 @@ fn renderSwitchCase(
     // Render everything before the arrow
     if (switch_case.ast.values.len == 0) {
         try renderToken(r, switch_case.ast.arrow_token - 1, .space); // else keyword
-    } else if (switch_case.ast.values.len == 1 and !has_comment_before_arrow) {
-        // render on one line and drop the trailing comma if any
-        try renderExpression(r, switch_case.ast.values[0], .space);
     } else if (trailing_comma or has_comment_before_arrow) {
         // Render each value on a new line
         try renderExpressions(r, switch_case.ast.values, .comma);