Merge pull request #4511 from lukaszstolarczuk/update-pmemobj_alloc-m…

…anpage

doc: update pmemobj_alloc.3

doc/libpmemobj/pmemobj_alloc.3.md

@@ -98,10 +98,13 @@ failure or system crash, on recovery they are guaranteed to be entirely complete
 or discarded, leaving the persistent memory heap and internal object containers
 in a consistent state.
 
-All these functions can be used outside transactions. Note that operations
-performed using the non-transactional API are considered durable after
-completion, even if executed within an open transaction. Such non-transactional
-changes will not be rolled back if the transaction is aborted or interrupted.
+All these functions should be used outside transactions. If executed within
+an open transaction they are considered durable immediately after completion.
+Changes made with these functions will not be rolled back if the transaction
+is aborted or interrupted. They have no information about other changes made
+by transactional API, so if the same data is modified in a single transaction
+using transactional and then non-transactional API, transaction abort
+will likely corrupt the data.
 
 The allocations are always aligned to a cache-line boundary.