chore: add prettier terraform formatting in markdown files (#134)

git-commit-signing/README.md

@@ -16,10 +16,10 @@ Please observe that using the SSH key that's part of your Coder account for comm
 
 This module has a chance of conflicting with the user's dotfiles / the personalize module if one of those has configuration directives that overwrite this module's / each other's git configuration.
 
-```hcl
+```tf
 module "git-commit-signing" {
-  source = "registry.coder.com/modules/git-commit-signing/coder"
-  version = "1.0.0"
+  source   = "registry.coder.com/modules/git-commit-signing/coder"
+  version  = "1.0.0"
   agent_id = coder_agent.example.id
 }
 ```