Test \{,re}newcommand arguments

Closes jgm#4470

Author: silby

test/command/4470.md

@@ -0,0 +1,27 @@
+```
+% pandoc -r latex -w plain
+\newcommand{\foo}{123}\renewcommand\foo{456}\foo
+^D
+456
+```
+
+```
+% pandoc -r latex -w plain
+\newcommand\foo{123}\renewcommand\foo{456}\foo
+^D
+456
+```
+
+```
+% pandoc -r latex -w plain
+\newcommand{\foo}{123}\renewcommand{\foo}{456}\foo
+^D
+456
+```
+
+```
+% pandoc -r latex -w plain
+\newcommand\foo{123}\renewcommand{\foo}{456}\foo
+^D
+456
+```