Fix `MULTILINES` regex to also match "\n\n"
We want to catch errors on multiple lines, t.i. the string contains a
`\n` plus *any* other character (the `.`) including other newline chars
(`(?s)`).
Note: We don't just look for a single `\n` because linters might report
exactly on the EOL position.
@@ -66,7 +66,7 @@ SOME_WS = re.compile(r'\s')
FALLBACK_MARK_STYLE = 'outline'
WS_ONLY = re.compile(r'^\s+$')
-MULTILINES = re.compile('\n(?=.)')
+MULTILINES = re.compile('(?s)\n(?=.)')
# Sublime >= 4074 supports underline styles on white space
# https://github.com/sublimehq/sublime_text/issues/137
