Check if builtin cd is called

Fixes #1234

src/ShellCheck/ASTLib.hs

@@ -261,7 +261,7 @@ getCommand t =
 getCommandName t = do
     (T_SimpleCommand _ _ (w:rest)) <- getCommand t
     s <- getLiteralString w
-    if "busybox" `isSuffixOf` s
+    if "busybox" `isSuffixOf` s || "builtin" == s
         then
             case rest of
                 (applet:_) -> getLiteralString applet

src/ShellCheck/Analytics.hs

@@ -2483,6 +2483,7 @@ prop_checkUncheckedCd5 = verifyTree checkUncheckedCdPushdPopd "if true; then cd
 prop_checkUncheckedCd6 = verifyNotTree checkUncheckedCdPushdPopd "cd .."
 prop_checkUncheckedCd7 = verifyNotTree checkUncheckedCdPushdPopd "#!/bin/bash -e\ncd foo\nrm bar"
 prop_checkUncheckedCd8 = verifyNotTree checkUncheckedCdPushdPopd "set -o errexit; cd foo; rm bar"
+prop_checkUncheckedCd9 = verifyTree checkUncheckedCdPushdPopd "builtin cd ~/src; rm -r foo"
 prop_checkUncheckedPushd1 = verifyTree checkUncheckedCdPushdPopd "pushd ~/src; rm -r foo"
 prop_checkUncheckedPushd2 = verifyNotTree checkUncheckedCdPushdPopd "pushd ~/src || exit; rm -r foo"
 prop_checkUncheckedPushd3 = verifyNotTree checkUncheckedCdPushdPopd "set -e; pushd ~/src; rm -r foo"