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 */
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index cdda613..ee32495 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -3074,6 +3074,24 @@
       'func Test() # comment',
       'endfunc',
       ], 'E488:')
+
+  var lines =<< trim END
+      vim9script
+      syn region Text
+      \ start='foo'
+      #\ comment
+      \ end='bar'
+  END
+  CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      syn region Text
+      \ start='foo'
+      "\ comment
+      \ end='bar'
+  END
+  CheckScriptFailure(lines, 'E399:')
 enddef
 
 def Test_vim9_comment_gui()
diff --git a/src/version.c b/src/version.c
index aaf27c1..188bb1a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2925,
+/**/
     2924,
 /**/
     2923,