Dry_run requires Debug level logging & no squigglies#23

Hey, just installed iwyu 0.24, working on WSL Ubuntu. Enabling the "dry run" setting, the only output visible is "[info]: IWYU edited 1 files on your behalf." Setting logging to Debug level shows a git diff-like output. I suggest enabling the log in Info level, as switching to Debug level is not intuitive. Second, I get no squiggly lines on the editor at all, even though I can call the extension with the Command Palette to produce output.