Fix conversion issues.

site/two-spaces.md

@@ -67,7 +67,7 @@ whether it's a sentence.
 But this is only true if the abbreviation can be used in only one way!  Read
 this sentence:
 
-``
+```
 I used to eat couches bef. I found the cow.
 ```
 
@@ -101,7 +101,9 @@ won't write about that.  The interesting thing is: How does this mix with using
 two spaces between sentences?  This can actually be a problem; look at this
 sentence:
 
-: Bla bla bla bla bef. bla bla.
+```
+Bla bla bla bla bef. bla bla.
+```
 
 This is one sentence, as "bef." does not end the sentence.  If we assume that
 the line width is not 80 characters, but instead 16 characters, then the line