updated README

README.md

@@ -4,7 +4,7 @@ Provides simple HTTP file server; Its so simple to do with golang; looks like no
 
 ## Installation
 
-```shell
+```bash
 go install git.thirdage.dev/night/handler@latest
 ```
 
@@ -13,7 +13,7 @@ go install git.thirdage.dev/night/handler@latest
 
 Calling without any arguments defaults to serving `./` at `0.0.0.0:8080`
 
-```shell
+```bash
 ./handler
 ```
 
@@ -23,6 +23,6 @@ Calling without any arguments defaults to serving `./` at `0.0.0.0:8080`
 - `p` sets port
 - `d` sets directory to serve
 
-```shell
+```bash
 ./handler -a 127.0.0.1 -p 3000 -d ./foo/bar
 ```