patch 9.0.1083: empty and comment lines in a class cause an error

Problem:    Empty and comment lines in a class cause an error.
Solution:   Skip empty and comment lines. (closes #11734)
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index 5ec606e..f45e3fa 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -131,6 +131,7 @@
         this.lnum: number
         this.col: number
 
+        # make a nicely formatted string
         def ToString(): string
           return $'({this.lnum}, {this.col})'
         enddef
@@ -155,6 +156,7 @@
         this.lnum: number = 1
         this.col: number = 1
 
+        # constructor with only the line number
         def new(lnum: number)
           this.lnum = lnum
         enddef
diff --git a/src/version.c b/src/version.c
index 4baa1b3..877fe75 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1083,
+/**/
     1082,
 /**/
     1081,
diff --git a/src/vim9class.c b/src/vim9class.c
index a91a4a5..94fe9e2 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -248,6 +248,16 @@
 	    break;
 	char_u *line = skipwhite(theline);
 
+	// Skip empty and comment lines.
+	if (*line == NUL)
+	    continue;
+	if (*line == '#')
+	{
+	    if (vim9_bad_comment(line))
+		break;
+	    continue;
+	}
+
 	char_u *p = line;
 	if (checkforcmd(&p, "endclass", 4))
 	{