docs: Fix mentions to 'all events' (#350)

When the examples and accompanying documentation were written, 'all
events' meant 'error events'.  With transactions added to the SDK,
BeforeSend is only applied to error events while all EventProcessor
functions (on client, scope or global) are applied to all outgoing
events (errors and transactions).

example/recover-repanic/main.go

@@ -102,7 +102,7 @@ func RecoverRepanic(f func()) {
 	// Add an EventProcessor to the scope. The event processor is a function
 	// that can change events before they are sent to Sentry.
 	// Alternatively, see also ClientOptions.BeforeSend, which is a special
-	// event processor applied to all events.
+	// event processor applied to error events.
 	hub.ConfigureScope(func(scope *sentry.Scope) {
 		scope.AddEventProcessor(func(event *sentry.Event, hint *sentry.EventHint) *sentry.Event {
 			filterFrames(event)

example/with_extra/main.go

@@ -67,7 +67,7 @@ func main() {
 		Dsn:   "https://hello@world.io/1337",
 		BeforeSend: func(event *sentry.Event, hint *sentry.EventHint) *sentry.Event {
 			// Solution 1 (use beforeSend, which will be applied to
-			// all events and is usually application specific):
+			// error events and is usually application specific):
 			if ex, ok := hint.OriginalException.(CustomComplexError); ok {
 				for key, val := range ex.GimmeMoreData() {
 					event.Extra[key] = val
@@ -80,9 +80,9 @@ func main() {
 		},
 		Transport: &devNullTransport{},
 
-		// Solution 2 (use custom integration, which will also be
-		// applied to all events, but can be easily extracted even as a
-		// separate utility and reused across all your projects):
+		// Solution 2 (use custom integration, which will be
+		// applied to all events, and can be extracted as a
+		// separate utility and reused across projects):
 		Integrations: func(integrations []sentry.Integration) []sentry.Integration {
 			return append(integrations, new(ExtractExtra))
 		},