doc/src/misc/hashchain/hashchain.md: Wrap lines at 72 columns

doc/src/misc/hashchain/hashchain.md

@@ -19,7 +19,7 @@ enum EventAction { ... };
 ## Event
 
 | Description            | Data Type      | Comments                    |
-|----------------------- | -------------- | --------------------------- |
+| ---------------------- | -------------- | --------------------------- |
 | previous_event_hash    | `EventId`      | Hash of the previous `Event`|
 | action                 | `EventAction`  | `Event`'s action            |
 | timestamp              | u64            | `Event`'s timestamp         |
@@ -27,19 +27,21 @@ enum EventAction { ... };
 ## EventNode
 
 | Description    | Data Type              | Comments                                              |
-|--------------- | ---------------------- | ----------------------------------------------------- |
+| -------------- | ---------------------- | ----------------------------------------------------- |
 | parent         | Option<`EventId`>      | Only current root has this set to None                |
 | event          | `Event`                | The `Event` itself                                    |
 | children       | Vec<`EventId`>         | The `Event`s which has parent as this `Event` hash    |
 
 ## Model
 
-The `Model` consists of chains (`EventNodes`) structured as a tree; whereby, each chain has an `Event`-based
-list. To maintain a strict order of chains, each `Event` depends on the hash of the previous `Event`.
-All of the chains share a root `Event` to preserve the tree structure.
+The `Model` consists of chains (`EventNodes`) structured as a tree;
+whereby, each chain has an `Event`-based list. To maintain a strict
+order of chains, each `Event` depends on the hash of the previous
+`Event`. All of the chains share a root `Event` to preserve the tree
+structure.
 
 | Description   | Data Type                        | Comments                      |
-|-------------- | -------------------------------- | ----------------------------- |
+| ------------- | -------------------------------- | ----------------------------- |
 | current_root  | `EventId`                        | The root `Event` for the tree |
 | orphans       | HashMap<`EventId`, `Event`>      | Recently added `Event`s       |
 | event_map     | HashMap<`EventId`, `EventNode`>  | The actual tree               |
@@ -47,52 +49,57 @@ All of the chains share a root `Event` to preserve the tree structure.
 
 ## View
 
-The `View` checks the `Model` for new `Event`s and then dispatches these `Event`s to the clients.
+The `View` checks the `Model` for new `Event`s and then dispatches
+these `Event`s to the clients.
 
-`Event`s are sorted according to the timestamp attached to each `Event`.
+`Event`s are sorted according to the timestamp attached to each
+`Event`.
 
 | Description   | Data Type                     | Comments               |
-|-------------- | ----------------------------- | ---------------------- |
+| ------------- | ----------------------------- | ---------------------- |
 | seen          | HashMap<`EventId`, `Event`>   | A list of `Event`s     |
 
 ## EventsQueue
 
 The `EventsQueue` used to transport the event from `Model` to `View`.
 
-The `Model` fills the `EventsQueue` with the new `Event`, while the `View` continuously
-fetches `Event`s from queue.
+The `Model` fills the `EventsQueue` with the new `Event`, while the
+`View` continuously fetches `Event`s from queue.
 
 # Architecture
 
-Tau uses Model–view software architecture. All of the operations, main data structures,
-and message handling from the network protocol happen on the `Model` side.
-Further, this keeps the `View` independent of the `Model`
-and allows the `View` to focus on receiving continuous updates from it.
+Tau uses Model–view software architecture. All of the operations, main
+data structures, and message handling from the network protocol happen
+on the `Model` side. Further, this keeps the `View` independent of the
+`Model` and allows the `View` to focus on receiving continuous updates
+from it.
 
 ## Add new `Event`
 
-Upon receiving a new `Event` from the network protocol, the `Event` will be added to the
-orphans list.
+Upon receiving a new `Event` from the network protocol, the `Event`
+will be added to the orphans list.
 
-After the ancestor of the new orphan is found, the orphan `Event` will be added to the chain
-according to its ancestor.
+After the ancestor of the new orphan is found, the orphan `Event` will
+be added to the chain according to its ancestor.
 
-For example: in [Example1](#example1) below, an `Event` is added to the first chain if
-its previous hash is Event-A1.
+For example: in [Example1](#example1) below, an `Event` is added to the
+first chain if its previous hash is Event-A1.
 
 ## Remove old leaves
 
-Remove leaves which are too far from the head leaf (the leaf in the longest chain).
+Remove leaves which are too far from the head leaf (the leaf in the
+longest chain).
 
-The depth difference from the common ancestor between a leaf to be removed and a head leaf
-must be greater than `MAX_DEPTH`.
+The depth difference from the common ancestor between a leaf to be
+removed and a head leaf must be greater than `MAX_DEPTH`.
 
 ## Update the root
 
-Finding the highest common ancestor for the leaves and assign it as the root
-for the tree.
+Finding the highest common ancestor for the leaves and assign it as the
+root for the tree.
 
-The highest common ancestor must have a height greater than `MAX_HEIGHT`.
+The highest common ancestor must have a height greater than
+`MAX_HEIGHT`.
 
 ## Example1