cst: Add ostream operator for chunk state

(cherry picked from commit 963a5d3)

src/v/cloud_storage/segment_chunk.cc

@@ -12,6 +12,17 @@
 
 namespace cloud_storage {
 
+std::ostream& operator<<(std::ostream& os, chunk_state c) {
+    switch (c) {
+    case chunk_state::not_available:
+        return os << "not available";
+    case chunk_state::download_in_progress:
+        return os << "download in progress";
+    case chunk_state::hydrated:
+        return os << "hydrated";
+    }
+}
+
 std::strong_ordering
 segment_chunk::operator<=>(const segment_chunk& chunk) const {
     const auto cmp = required_by_readers_in_future

src/v/cloud_storage/segment_chunk.h

@@ -30,6 +30,8 @@ enum class chunk_state {
     hydrated,
 };
 
+std::ostream& operator<<(std::ostream& os, chunk_state);
+
 struct segment_chunk {
     chunk_state current_state;