I've reworked the autocomplete parser to more closely match Newton, the
Fig-compatible parser I prototyped earlier this year. I was able to move
a lot faster by reusing patterns that inshellisense proved out, such as
for templates and generators.
I also support some features that inshellisense doesn't, like proper
combining of Posix-compatible flags, handling of option argument
separators, and handling of cursors in insertValues.