Clarified readme "instruments" section (#2607)

Task/Issue URL: https://app.asana.com/0/414235014887631/1206915607562737/f

documentation change only
normalized capitalization and grammar

README.md

@@ -31,12 +31,12 @@ We use [SwifLint](https://github.com/realm/SwiftLint) for enforcing Swift style
 
 ### Instruments
 
-We have Custom Instruments tool to help visualize and track events that happen during runtime.
+We have a Custom Instruments tool to help visualize and track events that happen during runtime.
 
 In order to run it:
-1. Build a Debug version and install it on Simulator/Device.
-2. Select Instruments target and run it on a Mac.  A New instance of Instruments app will be run that has a grayed out icon indicating that it works in debug mode with custom instruments attached.
-3. Select 'DDG Trace' template or set up a custom one by importing 'DDG Timeline' instrument from Library.
+1. Build a debug version and install it on a simulator or device.
+2. Select the Instruments target and run it on a Mac. A new instance of the Instruments app will run. It will have a grayed out icon indicating that it works in debug mode with custom instruments attached.
+3. Select the 'DDG Trace' template or set up a custom one by importing the 'DDG Timeline' instrument from Library.
 4. Start recording.
 
 See [Instruments Developer Help](https://help.apple.com/instruments/developer/mac/current/) for reference how to create custom instruments.