Add headers to licenses code snippets (#364)

docs/src/checks/licenses/cfg.md

@@ -201,13 +201,15 @@ It's often not useful or wanted to check for licenses in your own private worksp
 If `true`, workspace members will not have their license expression checked if they are not published.
 
 ```ini
+# Cargo.toml
 [package]
 name = "sekret"
 license = "¯\_(ツ)_/¯"
 publish = false # "private"!
 ```
 
 ```ini
+# deny.toml
 [licenses]
 # The sekret package would be ignored now
 private = { ignore = true }
@@ -218,13 +220,15 @@ private = { ignore = true }
 A list of private registries you may publish your workspace crates to. If a workspace member **only** publishes to private registries, it will also be ignored if `private.ignore = true`
 
 ```ini
+# Cargo.toml
 [package]
 name = "sekret"
 license = "¯\_(ツ)_/¯"
 publish = ["sauce"]
 ```
 
 ```ini
+# deny.toml
 [licenses]
 # Still ignored!
 private = { ignore = true, registries = ["sauce"] }