patch 8.2.3530: ":buf \{a}" fails while ":edit \{a}" works

Problem:    ":buf \{a}" fails while ":edit \{a}" works.
Solution:   Unescape "\{". (closes #8917)
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 481c94f..8a14a85 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -1147,7 +1147,8 @@
 				    while ((e = vim_strchr(s, '\n')) != NULL)
 				    {
 					*e = NUL;
-					p = vim_strsave_fnameescape(s, FALSE);
+					p = vim_strsave_fnameescape(s,
+								     VSE_NONE);
 					if (p != NULL)
 					{
 					    ga_concat(&ga, p);