patch 8.2.1573: Vim9: getreg() does not take "true" as argument

Problem:    Vim9: getreg() does not take "true" as argument.
Solution:   Use tv_get_bool_chk().  (closes #6820)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 69f7816..340ecf0 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -3336,9 +3336,9 @@
 	error = strregname == NULL;
 	if (argvars[1].v_type != VAR_UNKNOWN)
 	{
-	    arg2 = (int)tv_get_number_chk(&argvars[1], &error);
+	    arg2 = (int)tv_get_bool_chk(&argvars[1], &error);
 	    if (!error && argvars[2].v_type != VAR_UNKNOWN)
-		return_list = (int)tv_get_number_chk(&argvars[2], &error);
+		return_list = (int)tv_get_bool_chk(&argvars[2], &error);
 	}
     }
     else
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index cf48ba8..8d8e0d4 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -1503,6 +1503,12 @@
   close
 enddef
 
+def Test_getreg()
+  let lines = ['aaa', 'bbb', 'ccc']
+  setreg('a', lines)
+  assert_equal(lines, getreg('a', true, true))
+enddef
+
 def Test_recursive_call()
   assert_equal(6765, Fibonacci(20))
 enddef
diff --git a/src/version.c b/src/version.c
index c674148..886cd4e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1573,
+/**/
     1572,
 /**/
     1571,