readme: prepend bash for proper formatting

README.mkdn

@@ -8,17 +8,17 @@ To get started with Android/AmogOS, you'll need to get
 familiar with [Repo](https://source.android.com/source/using-repo.html) and [Version Control with Git](https://source.android.com/source/version-control.html).
 
 To initialize your local repository using the LMODroid trees, use a command like this:
-```
+```bash
 repo init -u https://github.com/AmogOS-Rom/android_manifest/ -b thirteen --git-lfs
 ```
 
 Then to sync up:
-```
+```bash
 repo sync -c -j$(nproc --all) --force-sync --no-clone-bundle --no-tags
 ```
 
 Before building you can set environment variables to include gapps or microg.
-```
+```bash
 # include gapps in the build
 export GAPPS=true
 
@@ -30,7 +30,7 @@ unset GAPPS
 ```
 
 To start the build you should run the following commands.
-```
+```bash
 source build/envsetup.sh
 
 # replace $codename with the actual codename of your device