docs: unify code and shell cmd blocks

docs/grpc/javascript.md

@@ -121,7 +121,7 @@ invoice.
 
 This example has a few dependencies:
 ```shell
-npm install --save async lodash bytebuffer
+⛰  npm install --save async lodash bytebuffer
 ```
 
 You can run the following in your shell or put it in a program and run it like