fix(typegen): don't let semicolons cause queries to be executed

[mmkal]

It was possible to make psql accidentally execute statements if they ended with a semicolon. The problem:

echo 'create table foo1(id int); \gdesc' | psql -f -

Actually executes create table foo(id int) and ignores the \gdesc part as an invalid command. This works around by banning semicolons altogether unless they're the last character, in which case they'll be trimmed. Parsing the query would probably be better but it's harder to be sure it's safe that way.

[janpaepke]

Woah! Good find!