Fix exponential backtracking

Author: DmitrySharabin

src/languages/dotenv.js

@@ -49,7 +49,7 @@ export default {
 				},
 				{
 					pattern:
-						/(?<==\s*)(?:(['"`])(?:\\.|(?!\1)[\s\S])*?\1|\S.*?\S)(?=\s*$|\s+#.*$)/m,
+						/(?<==\s*)(?:(['"`])(?:\\[\s\S]|(?!\1)[^\\])*?\1|\S(?:.*?\S)?)(?=\s*$|\s+#.*$)/m,
 					alias: 'string',
 					inside: {
 						'command-substitution': {