Add missing types

Part-of: <https://gitlab.freedesktop.org/libinput/libei/-/merge_requests/392>

doc/protocol/doc/ei-scanner.md

@@ -55,6 +55,8 @@ ei-scanner additionally provides the following values to the Jinja2 templates:
       from the protocol XML type:
         uint32 -> "u"
         int32 -> "i"
+        uint64 -> "t"
+        int64 -> "x"
         float -> "f"
         fd -> "h"
         new_id -> "n"