add language markers to readme

README.md

@@ -6,7 +6,7 @@ pipe multiple invocations to create more complex operations. However, a single i
 An example invocation, used to adapt a full-length subtitle track to a shorter version of "Whisper of the Heart", looks
 like this:
 
-```
+```bash
 srtune source.srt -o whisper.srt -M235=15:06.7 -M309=24:15 -M412=32:12 \
   -M411=32:01 -M762=58:51 -M895=1:08:33 -M1125=1:26:28 -M01:44:22=01:41:37.3
 ```
@@ -29,7 +29,7 @@ work out the right set of arguments. The flag '--renumber' will give each output
 note that, once renumbered, the indices in the output file should no longer be used in the command invocation, as there
 can be (and often will be) differences from the original file.
 
-```
+```none
 USAGE:
     srtune [FLAGS] [OPTIONS] [--] [INFILE]