chore(AIP-193): fix capitalization of bullets for consistency. (#1417)

Author: shwoodard

aip/general/0193.md

@@ -90,8 +90,8 @@ Services must return a [`google.rpc.Status`][Status] message when an API
 error occurs. For each error the service **must** populate the `message`
 string in [`google.rpc.Status`][Status] as follows:
 
-- present a developer-facing, human-readable "debug message"
-- present the message in the service's native language to explain both
+- Present a developer-facing, human-readable "debug message"
+- Present the message in the service's native language to explain both
   the error and offer an actionable resolution to it ([citation][Error
   model])