inconsistent behavior of wrap_comments (merges short lines in lists)

[xxchan]

 /// a
 ///    b
 ///
 /// a
 /// b
 ///
 /// - a
 /// b
-/// - a
-///   b
+/// - a b
 fn main() {}

Why is only the last one wrapped? Is this expected behavior, or limitation of the implementation?

rustfmt 1.6.0-nightly (0e8e857b 2023-07-16)

[xxchan]

This is wrapped (we don't want 🤔️)
    // 1. logical_scan ->  logical_join
    //                      /        \
    //                index_scan   primary_table_scan

But this is not.
    //    logical_scan ->  logical_join
    //                      /        \
    //                index_scan   primary_table_scan

[xxchan]

i.e., short lines are only merged for list