Tiny document fixes [ci skip]

Add a missing capital letter and avoid using absolute links to the
API because they may refer to out-dated documentation on the Edge
site.

actionpack/lib/action_controller/metal/conditional_get.rb

@@ -129,7 +129,7 @@ def fresh_when(object = nil, etag: nil, weak_etag: nil, strong_etag: nil, last_m
     # * <tt>:etag</tt> Sets a "weak" ETag validator on the response. See the
     #   +:weak_etag+ option.
     # * <tt>:weak_etag</tt> Sets a "weak" ETag validator on the response.
-    #   requests that set If-None-Match header may return a 304 Not Modified
+    #   Requests that set If-None-Match header may return a 304 Not Modified
     #   response if it matches the ETag exactly. A weak ETag indicates semantic
     #   equivalence, not byte-for-byte equality, so they're good for caching
     #   HTML pages in browser caches. They can't be used for responses that

activerecord/lib/active_record/associations.rb

@@ -300,7 +300,7 @@ def association_instance_set(name, association)
     #
     # === A word of warning
     #
-    # Don't create associations that have the same name as [instance methods](http://api.rubyonrails.org/classes/ActiveRecord/Core.html) of
+    # Don't create associations that have the same name as {instance methods}[rdoc-ref:ActiveRecord::Core] of
     # <tt>ActiveRecord::Base</tt>. Since the association adds a method with that name to
     # its model, using an association with the same name as one provided by <tt>ActiveRecord::Base</tt> will override the method inherited through <tt>ActiveRecord::Base</tt> and will break things.
     # For instance, +attributes+ and +connection+ would be bad choices for association names, because those names already exist in the list of <tt>ActiveRecord::Base</tt> instance methods.