Suggestion: print a warning if a command might contain multiple statements

My Clojure is a little rusty so I can’t open a PR for this right now, but I’d like to at least make this suggestion because I just lost an hour trying to debug why my giant migration wasn’t working… turns out my migration contained dozens of statements as a single “command” — i.e. it wasn’t using the delimiter that is required as per the readme.

My rationale for this suggestion is that:

• This just cost me an hour, and while I am rusty with Clojure, I am pretty experienced
• I’ve found multiple other issues opened by people who encountered this problem over the years
  • it’s just very easy to miss that bit in the readme
  • especially since some other migrations frameworks do support multiple statements in a single .sql file
• I would think it could be fairly easy to implement
  • e.g. something as simple as checking whether a command contains two or more instances of a semicolon followed by a linefeed might be helpful