fix(foundations): reserve can fail even with +16 flag set

foundations/actions/reserve.mdx

@@ -31,16 +31,15 @@ Notation:
 - `amount` – the amount of Toncoin passed to the `RAWRESERVE` instruction.
 - `mode` – the integer mode passed to the `RAWRESERVE` instruction.
 - `original_balance`:
-  - if after the storage phase, account's balance is less than the value of incoming message with bounce flag set to `false`, then `original_balance` is set to $0$;
+  - if after the storage phase, account's balance is less than the value of incoming message with bounce flag set to `false`, then `original_balance` is set to 0;
   - otherwise, `original_balance` equals account's balance before the compute phase minus incoming message value.
 - `remaining_balance` – account's balance before the reservation action.
 - `reserve` – the final amount to be reserved.
 
 The algorithm is as follows:
 
 1. Check that `mode` has flag `ReserveBounceIfActionFail`:
-   - if so, then in case of any failure the action phase will be interrupted and the bounce phase will be initiated;
-   - if not, then in case of any failure the reservation action will be skipped.
+   - if so, then in case of any failure during reservation, the [bounce phase](/foundations/phases#bounce-phase) is initiated.
 1. Set `reserve` to `amount`.
 1. Check that `mode` has flag `ReserveAddOriginalBalance`:
    1. If so, then check that `mode` has flag `ReserveInvertSign`:
@@ -86,4 +85,4 @@ The following errors can occur during the reservation flow:
 - Some problems with unpacking the reserve action cell.
 - A problem related to extra-currency.
 
-If the action had flag `16`, then in case of any of the above errors a [bounce message](/foundations/messages/internal#bounces) is sent back to a sender.
+If the action had flag `16`, i.e., `ReserveBounceIfActionFail`, then in case of any of the above errors the transaction enters the [bounce phase](/foundations/phases#bounce-phase).

foundations/messages/internal.mdx

@@ -93,8 +93,8 @@ A bounce message is used to inform the sender that handling of their message fai
 - there is enough Toncoin to send it left from handling the failed message,
 - and the message is bounceable,
 - and when either
-  - a message throws an error from the [compute phase](/foundations/phases#compute-phase) during message processing and state was not committed by [`COMMIT`](/tvm/instructions#f80f-commit) TVM instruction,
-  - or a message throws an error in the [action phase](/foundations/phases#action-phase) and mode [`SendBounceIfActionFail`](/foundations/messages/modes) is used.
+  - a contract throws an error from the [compute phase](/foundations/phases#compute-phase) during message processing, and the state was not committed by [`COMMIT`](/tvm/instructions#f80f-commit) TVM instruction,
+  - or an action fails in the [action phase](/foundations/phases#action-phase) with the `+16` flag enabled, for example [`SendBounceIfActionFail`](/foundations/messages/modes) in case of message sends or [`ReserveBounceIfActionFail`](/foundations/actions/reserve#modes) in case of reservations.
 
 ### Default bounce