style: スタイルを修正

src/main/kotlin/dev/usbharu/hideout/service/core/MdcXrequestIdFilter.kt

@@ -21,6 +21,6 @@ class MdcXrequestIdFilter : Filter {
     }
 
     companion object {
-        val KEY = "x-request-id"
+        private const val KEY = "x-request-id"
     }
 }

src/main/kotlin/dev/usbharu/hideout/service/post/PostServiceImpl.kt

@@ -35,7 +35,7 @@ class PostServiceImpl(
     private suspend fun internalCreate(post: Post, isLocal: Boolean): Post {
         val save = try {
             postRepository.save(post)
-        } catch (e: ExposedSQLException) {
+        } catch (_: ExposedSQLException) {
             postQueryService.findByApId(post.apId)
         }
         timelineService.publishTimeline(save, isLocal)

src/main/kotlin/dev/usbharu/hideout/service/user/UserServiceImpl.kt

@@ -67,7 +67,7 @@ class UserServiceImpl(
         )
         return try {
             userRepository.save(userEntity)
-        } catch (e: ExposedSQLException) {
+        } catch (_: ExposedSQLException) {
             userQueryService.findByUrl(user.url)
         }
     }