Two-letter token lookup table for tokens 128-159. See the deep dive on
"Printing text tokens" for details of how the two-letter token system works.
These two-letter tokens can also be used in the extended text token system, by
adding 100 to the token number. So the extended two-letter token 228 is "AL",
the same as the standard two-letter token 128. In this system, the last four
tokens are not available, as they would have numbers greater than 255.