alternator,streaming: fix comment typos

Fix misspellings in comments identified by the codespell tool.
fix typos in comment

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

Closes scylladb/scylladb#22829

alternator/executor.cc

@@ -1259,7 +1259,7 @@ regular_column_transformation::result extract_from_attrs_column_computation::com
 }
 
 // extract_from_attrs_column_computation needs the whole row to compute
-// value, it cann't use just the partition key.
+// value, it can't use just the partition key.
 bytes extract_from_attrs_column_computation::compute_value(const schema&, const partition_key&) const {
     on_internal_error(elogger, "extract_from_attrs_column_computation::compute_value called without row");
 }
@@ -1575,7 +1575,7 @@ future<executor::request_return_type> executor::create_table(client_state& clien
 // in a AttributeDefinitions. If one of these key columns are *already* key
 // columns of the base table or any of its prior GSIs or LSIs, the type
 // given in AttributeDefinitions must match the type of the existing key -
-// otherise Alternator will not know which type to enforce in new writes.
+// otherwise Alternator will not know which type to enforce in new writes.
 // This function checks for such conflicts. It assumes that the structure of
 // the given attribute_definitions was already validated (with
 // validate_attribute_definitions()).

streaming/stream_blob.hh

@@ -92,7 +92,7 @@ public:
     streaming::file_ops fops;
     service::frozen_topology_guard topo_guard;
     std::optional<sstables::sstable_state> sstable_state;
-    // We can extend this verb to send arbitary blob of data
+    // We can extend this verb to send arbitrary blob of data
 };
 
 enum class store_result {