patch 8.2.1477: Vim9: error when using bufnr('%')

Problem:    Vim9: error when using bufnr('%').
Solution:   Don't give an error for using a string argument. (closes #6723)
diff --git a/src/evalbuffer.c b/src/evalbuffer.c
index df5270a..2d738f1 100644
--- a/src/evalbuffer.c
+++ b/src/evalbuffer.c
@@ -390,7 +390,8 @@
 	buf = curbuf;
     else
     {
-	(void)tv_get_number(&argvars[0]);    // issue errmsg if type error
+	if (argvars[0].v_type != VAR_STRING)
+	    (void)tv_get_number(&argvars[0]);    // issue errmsg if type error
 	++emsg_off;
 	buf = tv_get_buf(&argvars[0], FALSE);
 	--emsg_off;
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 38d613a..446ee4d 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -1315,6 +1315,11 @@
   assert_equal(6, res)
 enddef
 
+def Test_bufnr()
+  let buf = bufnr()
+  assert_equal(buf, bufnr('%'))
+enddef
+
 def Test_getreg_return_type()
   let s1: string = getreg('"')
   let s2: string = getreg('"', 1)
diff --git a/src/version.c b/src/version.c
index 734d2ba..e332c01 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1477,
+/**/
     1476,
 /**/
     1475,