Add syntax to blocks

Public/_posts/2018-05-02-view-controllers-make-crummy-navigators.textbundle/text.md

@@ -16,7 +16,7 @@ There is!
 
 If we treat view controllers like functional pieces, we can expose a small interface to interact with them and use delegation to get stuff out. Here’s a trivial example:
 
-```
+```swift
 protocol PeopleViewControllerDelegate: AnyObject {
     func personSelected(_ person: Person, from viewController: PeopleViewController)
 }

Public/_posts/2018-07-23-scripting-your-security.textbundle/text.md

@@ -15,7 +15,7 @@ My sample project uses a Vapor web server, but you can sub out anything you wish
 
 We start with a Dockerfile that will build up our nginx container:
 
-```
+```docker
 # build from the official Nginx image
 FROM nginx
 

Public/_posts/2019-01-23-mixed-language-framework.textbundle/text.md

@@ -30,7 +30,7 @@ If you're like me, you're a stickler for having clean API boundaries. This means
 
 First, in your framework's root, create a file called `module.map`. I don't know why it has to be this exact title, but it does. Here's its contents:
 
-```
+```objc
 module LanguageKit_Private {
     // import your private headers here
     export *