Improve documentation: fixed typos on Readme and added dollar sign at Contributing [ci skip]

Author: hudsonsferreira

CONTRIBUTING.md

@@ -47,8 +47,8 @@ Rake can be found at http://docs.seattlerb.org/rake/.
 
 To run a single test suite
 
-   rake test TEST=path/to/test.rb
+`$ rake test TEST=path/to/test.rb`
 
-which can be further narrowed down to one test:
+Which can be further narrowed down to one test:
 
-   rake test TEST=path/to/test.rb TESTOPTS="--name=test_something"
+`$ rake test TEST=path/to/test.rb TESTOPTS="--name=test_something"`

README.md

@@ -200,12 +200,12 @@ end
 #### Attributes
 
 It's the default adapter, it generates a json response without a root key.
-Doesn't follow any specifc convention.
+Doesn't follow any specific convention.
 
 #### JSON
 
 It also generates a json response but always with a root key. The root key **can't be overridden**, and will be automatically defined accordingly with the objects being serialized.
-Doesn't follow any specifc convention.
+Doesn't follow any specific convention.
 
 #### JSON API
 
@@ -271,7 +271,7 @@ the serializer generator:
 $ rails g serializer post
 ```
 
-The generated seralizer will contain basic `attributes` and
+The generated serializer will contain basic `attributes` and
 `has_many`/`has_one`/`belongs_to` declarations, based on the model. For example:
 
 ```ruby