Add missing __builtin_unreachable for switch/case for gcc

Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>

src/Common/FileSegment.cpp

@@ -437,6 +437,7 @@ String FileSegment::stateToString(FileSegment::State state)
         case FileSegment::State::SKIP_CACHE:
             return "SKIP_CACHE";
     }
+    __builtin_unreachable();
 }
 
 String FileSegmentsHolder::toString()

src/Disks/IO/CachedReadBufferFromRemoteFS.h

@@ -96,6 +96,7 @@ private:
             case ReadType::REMOTE_FS_READ_AND_PUT_IN_CACHE:
                 return "REMOTE_FS_READ_AND_PUT_IN_CACHE";
         }
+        __builtin_unreachable();
     }
     size_t first_offset = 0;
 };