README: Use GitHub Markdown code fences

README.md

@@ -9,21 +9,25 @@ provided by freedesktop.org (see http://freedesktop.org/wiki/Software/shared-mim
 Usage
 Usage
 =====
 =====
 
 
-    require 'mimemagic'
-    MimeMagic.by_extension('html').text?
-    MimeMagic.by_extension('.html').child_of? 'text/plain'
-    MimeMagic.by_path('filename.txt')
-    MimeMagic.by_magic(File.open('test.html'))
-    # etc...
+```ruby
+require 'mimemagic'
+MimeMagic.by_extension('html').text?
+MimeMagic.by_extension('.html').child_of? 'text/plain'
+MimeMagic.by_path('filename.txt')
+MimeMagic.by_magic(File.open('test.html'))
+# etc...
+```
 
 
 Extra magic overlay
 Extra magic overlay
 =====
 =====
 
 
 Microsoft Office 2007+ formats (xlsx, docx, and pptx) are not supported by the mime database at freedesktop.org. These files are all zipped collections of xml files and will be detected as "application/zip". Mimemagic comes with extra magic you can overlay on top of the defaults to correctly detect these file types. Enable it like this:
 Microsoft Office 2007+ formats (xlsx, docx, and pptx) are not supported by the mime database at freedesktop.org. These files are all zipped collections of xml files and will be detected as "application/zip". Mimemagic comes with extra magic you can overlay on top of the defaults to correctly detect these file types. Enable it like this:
 
 
-    require 'mimemagic'
-    require 'mimemagic/overlay'
-    MimeMagic.by_magic(File.open('test.xlsx'))
+```ruby
+require 'mimemagic'
+require 'mimemagic/overlay'
+MimeMagic.by_magic(File.open('test.xlsx'))
+```
 
 
 You can add your own magic with `MimeMagic.add`. See `lib/mimemagic/overlay.rb`.
 You can add your own magic with `MimeMagic.add`. See `lib/mimemagic/overlay.rb`.