Fix the master build: add the blank line that rescript-lang#8961 prints to the comment pattern snapshot (rescript-lang#9137)

Add the blank line before a multi-line let to the comment pattern snapshot

rescript-lang#9127 added list-pattern cases to printer/comments/pattern.res, and its
snapshot was made before rescript-lang#8961, which puts a blank line around multi-line
module items, was merged. Together they print a blank line before
`let f = x => switch x {…}`, and the syntax test of master has failed on it
since rescript-lang#9127.

Claude-Session: https://claude.ai/code/session_01Kbf3gLpf7RN1MiRcubPgRn

Signed-off-by: Christoph Knittel <ck@cca.io>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Pedro Castro <aspeddro@gmail.com>

Author: 2 people

tests/syntax_tests/data/printer/comments/expected/pattern.res.txt

@@ -53,6 +53,7 @@ let /* d */ r = list{1, 2}
 let r /* after */ = list{1, 2}
 let /* d1 */ /* d2 */ /* e */ r = list{1, 2}
 let f = /* d */ r => r
+
 let f = x =>
   switch x {
   /* d */ | r => r