Avoid storing duplicate trailing keyed components

There are often cases where after a single character difference the rest of the trailing characters in the keyed portion are identical. The duplication can be avoided by indicating all branches share the same trailing information. Interestingly there are also cases in some of the example files where the following options are identical. E.g.

X0M
X0F
X1M
X1F
Y0M
Y0F
Y1M
Y1F

The option (X|Y) are followed by exactly the same pattern which can be shared. This saved a few more bytes on some examples.