compileTranslationTable: Check replacement characters []

[sthibaul]

We can check at compile-time that we always have exactly one startReplace character followed by one endReplace.

This is needed otherwise when a table misses the endReplace (as tables/hu-hu-g1_braille_input.cti fixed here), match has startReplace != -1 but endReplace == -1, and eventually passDoAction sets newPos to -1, and other functions such as setBefore underflow the buffer.

[bertfrees]

Nice find.