chore: add commented reg_exp example with escape slash

config.toml

@@ -1,6 +1,8 @@
 be_quiet = false 
 [[targets]]
 input = "input.txt"
+# \ has to be escaped 
+reg_exp = "(\\d+) (\\w+) (\\d+)"
 
 [[targets]]
 input = "input_2.txt"