UEB capitalization needs work

[NSoiffer]

Test case braille::UEB::iceb::hat_12_1_7 is: $A\hat{B}C$.

The output uses a cap word indicator but the example doesn't. This is likely because the last part of the definition in section GTM 12 says "the item is simply the previous individual symbol". Symbol in this case includes the cap indicator. So it seems in this case, $\hat{B}$ should not be considered a cap letter.

The code in braille.rs that builds a cap word from caps needs modification to handle "symbols".

[NSoiffer]

The cap part is fixed by dcb0028cbc9864cfcedbdfedf9df33b397ca3256.

The change likely needs to be extended to type forms (language changes, bold, etc). Maybe not language changes. I need to read the spec more carefully.