[Docs] Some small fixes.

lib/cocoapods/installer/user_project_integrator/target_integrator/xcconfig_integrator.rb

@@ -31,7 +31,7 @@ module Pod
           #-------------------------------------------------------------------#
 
           # Removes the xcconfig used up to CocoaPods 0.33 from the project and
-          # deletes the file it if exists.
+          # deletes the file if it exists.
           #
           # @param  [Target::AggregateTarget] pod_bundle
           #         The Pods bundle.

lib/cocoapods/project.rb

@@ -193,7 +193,7 @@ module Pod
       podfile_ref
     end
 
-    # Adds a new build configuration to the project and populates its with
+    # Adds a new build configuration to the project and populates it with
     # default settings according to the provided type.
     #
     # @note   This method extends the original Xcodeproj implementation to