Update README.md for formatting & typos

Author: w-goog

Samples/Swift/DaysUntilBirthday/README.md

@@ -37,8 +37,12 @@ on our GitHub repo, and we retrieve these from the workflow environment.
 
 When run locally, both the email and password need to be passed to `xcodebuild`.
 
-From in Xcode, you can add arguments by selecting "Edit Scheme > Run > Environment Variables", and replace the variables with your test account. Alternatively, edit Credential.swift directly. WARNING: Don't check these into the repo!
+In Xcode, you can add arguments by selecting "Edit Scheme > Run > Environment Variables", and
+replace the variables with your test account. Alternatively, edit `Credential.swift` directly.
+WARNING: Don't check these into the repo!
 
-From the command line, you can do this as arguments: `xcodebuild <other args> EMAIL_SECRET=... PASSWORD_SECRET=...`.
+From the command line, you can do this as arguments:
+`xcodebuild <other args> EMAIL_SECRET=... PASSWORD_SECRET=...`.
 
-For Googlers, refer to CSI internal Workflow documentation for how to access these values, or access them via the repo's Secrets. 
+For Googlers, refer to CSI internal Workflow documentation for how to access these values, or access
+them via the repo's Secrets.