fix: address review feedback — gofmt NITs and remove unreachable default

- github/client.go: add missing blank line between doRequestWithBody and doJSONRequest
- cmd/review-bot/main.go: remove double blank line before findAllOwnReviews
- cmd/review-bot/main.go: remove unreachable default case in VCS client init switch
  (provider is already validated at startup)
- cmd/review-bot/main_test.go: remove double blank line before TestHasSharedToken
- cmd/review-bot/main_test.go: fix comment alignment (gofmt)
- review/persona_test.go: fix comment alignment in table literal (gofmt)

review/persona_test.go

@@ -355,7 +355,7 @@ func TestCapitalizeFirst(t *testing.T) {
 		{"HELLO", "HELLO"},
 		{"a", "A"},
 		{"", ""},
-		{"日本語", "日本語"}, // Non-ASCII: Japanese doesn't have case
+		{"日本語", "日本語"},     // Non-ASCII: Japanese doesn't have case
 		{"über", "Über"},   // German umlaut
 		{"élève", "Élève"}, // French accent
 	}