`zig fmt` does not support doc comments on function parameters without trailing comma

[Toxaris]

Zig Version

0.15.1

Steps to Reproduce

zig fmt --stdin <<EOF
fn f(
    /// comment
    x: u32,
    y: u32
) void {}
EOF

Observed Behavior

fn f(/// comment
x: u32, y: u32) void {}

Expected Behavior

fn f(
    /// comment
    x: u32,
    y: u32,
) void {}

Further thoughts

1. This means zig fmt is not idempotent because the following errors out ("same line documentation comment"):

   zig fmt --stdin <<EOF | zig fmt --stdin
   fn f(
       /// comment
       x: u32,
       y: u32
   ) void {}
   EOF

2. It works with a trailing comma after the last parameter:

   zig fmt --stdin <<EOF
   fn f(
       /// comment
       x: u32,
       y: u32,
   ) void {}
   EOF

3. It works for regular comments even without a trailing comma after the last parameter:

   zig fmt --stdin <<EOF
   fn f(
       // comment
       x: u32,
       y: u32
   ) void {}
   EOF

I found some issue about similar problems that are supposedly fixed. Maybe this got fixed in the past for // but not for /// for some reason?

[Vexu]

Duplicate of #18088