patch 8.2.2925: Vim9: line continuation comment uses legacy syntax

Problem:    Vim9: line continuation comment uses legacy syntax.
Solution:   Check for #\ instead of "\. (closes #8295)
diff --git a/src/scriptfile.c b/src/scriptfile.c
index 203cad0..15338be 100644
--- a/src/scriptfile.c
+++ b/src/scriptfile.c
@@ -1842,7 +1842,8 @@
 			ga_concat(&ga, p);
 		    }
 		}
-		else if (!(p[0] == '"' && p[1] == '\\' && p[2] == ' ')
+		else if (!(p[0] == (in_vim9script() ? '#' : '"')
+						&& p[1] == '\\' && p[2] == ' ')
 		     && !(do_vim9_all && (*p == NUL || vim9_comment_start(p))))
 		    break;
 		/* drop a # comment or "\ comment line */