Format bullets with * to match elsewhere (#2548)

See also commit b36c568 (Use * for bullet points in the metadata list,
2023-10-12) which makes the same change, for the same reason.

References: b36c568

Author: amartini51

proposals/0439-trailing-comma-lists.md

@@ -1,11 +1,11 @@
 # Allow trailing comma in comma-separated lists
 
-- Proposal: [SE-0439](0439-trailing-comma-lists.md)
-- Author: [Mateus Rodrigues](https://github.com/mateusrodriguesxyz)
-- Review Manager: [Xiaodi Wu](https://github.com/xwu)
-- Status: **Accepted with modifications**
-- Implementation: https://github.com/swiftlang/swift/pull/74522# gated behind `-enable-experimental-feature TrailingComma`
-- Review: ([pitch](https://forums.swift.org/t/pitch-allow-trailing-comma-in-tuples-arguments-and-if-guard-while-conditions/70170)), ([review](https://forums.swift.org/t/se-0439-allow-trailing-comma-in-comma-separated-lists/72876)), ([acceptance](https://forums.swift.org/t/accepted-with-modifications-se-0439-allow-trailing-comma-in-comma-separated-lists/73216))
+* Proposal: [SE-0439](0439-trailing-comma-lists.md)
+* Author: [Mateus Rodrigues](https://github.com/mateusrodriguesxyz)
+* Review Manager: [Xiaodi Wu](https://github.com/xwu)
+* Status: **Accepted with modifications**
+* Implementation: https://github.com/swiftlang/swift/pull/74522# gated behind `-enable-experimental-feature TrailingComma`
+* Review: ([pitch](https://forums.swift.org/t/pitch-allow-trailing-comma-in-tuples-arguments-and-if-guard-while-conditions/70170)), ([review](https://forums.swift.org/t/se-0439-allow-trailing-comma-in-comma-separated-lists/72876)), ([acceptance](https://forums.swift.org/t/accepted-with-modifications-se-0439-allow-trailing-comma-in-comma-separated-lists/73216))
 
 ## Introduction