Add SSH config syntax

Tested:
```
bash assets/create.sh
cargo build
target/debug/bat --language ssh_config ~/.ssh/config
```

.gitmodules

@@ -135,3 +135,6 @@
 [submodule "assets/syntaxes/DotENV"]
 	path = assets/syntaxes/DotENV
 	url = https://github.com/zaynali53/DotENV
+[submodule "assets/syntaxes/ssh-config"]
+	path = assets/syntaxes/ssh-config
+	url = https://github.com/robballou/sublimetext-sshconfig.git