Remove YAML implementation detail, as we're not trying to document all of

YAML's behavior in this guide. [ci skip]

guides/source/testing.md

@@ -80,7 +80,7 @@ steve:
   profession: guy with keyboard
 ```
 
-Each fixture is given a name followed by an indented list of colon-separated key/value pairs. Records are typically separated by a blank space. You can place comments in a fixture file by using the # character in the first column. Keys which resemble YAML keywords such as 'yes' and 'no' are quoted so that the YAML Parser correctly interprets them.
+Each fixture is given a name followed by an indented list of colon-separated key/value pairs. Records are typically separated by a blank space. You can place comments in a fixture file by using the # character in the first column.
 
 If you are working with [associations](/association_basics.html), you can simply
 define a reference node between two different fixtures. Here's an example with