Create wallet.md (MystenLabs#1021)

* Create wallet.md

Make Sui Network Gateway a proper noun and fix some grammar in that section

* Update wallet.md

Remove period from section header (trying to trigger checks too)

doc/src/build/wallet.md

@@ -48,7 +48,7 @@ newly created accounts.
 ## Wallet configuration
 The genesis process creates a configuration file `wallet.conf`, and a keystore file `wallet.key` for the
 Sui wallet.  The config file contains information of the accounts and
-the Sui network gateway. The keystore file contains all the public-private key pair of the created accounts.
+the Sui Network Gateway. The keystore file contains all the public-private key pair of the created accounts.
 Sui wallet uses the network information in `wallet.conf` to communicate
 with the Sui network authorities  and create transactions using the key
 pairs residing in the keystore file.
@@ -102,8 +102,9 @@ database. This database stores all the transaction data, certificates
 and object data belonging to the account.
 
 ### Sui Network Gateway
-The Sui network gateway is an abstraction layer that acts as the entry point to the Sui network.
-Different gateway implementation can be use by the application layer base on their use cases.
+The Sui Network Gateway (or simply, Sui Gateway) is an abstraction layer that acts as the entry
+point to the Sui network. Different gateway implementations can be used by the application layer
+based on their use cases.
 
 #### Embedded Gateway
 As the name suggests, embedded gateway embeds the gateway logic into the application;
@@ -259,7 +260,7 @@ The output shows a confirmation after the account has been created:
 Created new keypair for address : F456EBEF195E4A231488DF56B762AC90695BE2DD
 ```
 
-### Add existing accounts to `wallet.conf` manually.
+### Add existing accounts to `wallet.conf` manually
 
 If you have an existing key pair from an old wallet config, you can copy the account
 address manually to the new `wallet.conf`'s accounts section, and add the key pair to the keystore file;