docs: (cli) minor updates to deploy-a-program.md (#34307)

* docs: (cli) minor updates to deploy-a-program.md

* address review comments

* remove unnecessary impl details from the docs about deploy command upgrade flow

* clarify program redeploy section

---------

Co-authored-by: norwnd <norwnd>

docs/src/cli/deploy-a-program.md

@@ -13,8 +13,8 @@ To deploy a program, use the Solana tools to interact with the on-chain loader
 to:
 
 - Initialize a program account
-- Upload the program's shared object to the program account's data buffer
-- Verify the uploaded program
+- Upload the program's shared object (the program binary `.so`) to the program account's data buffer
+- (optional) Verify the uploaded program
 - Finalize the program by marking the program account executable.
 
 Once deployed, anyone can execute the program by sending transactions that
@@ -25,7 +25,7 @@ reference it to the cluster.
 ### Deploy a program
 
 To deploy a program, you will need the location of the program's shared object
-(the program binary .so)
+(the program binary `.so`):
 
 ```bash
 solana program deploy <PROGRAM_FILEPATH>
@@ -89,8 +89,9 @@ Data Length: 5216 (0x1460) bytes
 ### Redeploy a program
 
 A program can be redeployed to the same address to facilitate rapid development,
-bug fixes, or upgrades. Matching keypair files are generated once so that
-redeployments will be to the same program address.
+bug fixes, or upgrades. If a program id is not provided, the program will be 
+deployed to the default address at `<PROGRAM_NAME>-keypair.json`. This default 
+keypair is generated during the first program compilation.
 
 The command looks the same as the deployment command:
 
@@ -109,11 +110,6 @@ to become (plus some wiggle room).
 solana program deploy --max-len 200000 <PROGRAM_FILEPATH>
 ```
 
-Note that program accounts are required to be
-[rent-exempt](developing/programming-model/accounts.md#rent-exemption), and the
-`max-len` is fixed after initial deployment, so any SOL in the program accounts
-is locked up permanently.
-
 ### Resuming a failed deploy
 
 If program deployment fails, there will be a hanging intermediate buffer account
@@ -157,7 +153,7 @@ solana program deploy --buffer <KEYPAIR_PATH> <PROGRAM_FILEPATH>
 Both program and buffer accounts can be closed and their lamport balances
 transferred to a recipient's account.
 
-If deployment fails there will be a left over buffer account that holds
+If deployment fails there will be a left-over buffer account that holds
 lamports. The buffer account can either be used to [resume a
 deploy](#resuming-a-failed-deploy) or closed.
 
@@ -209,7 +205,7 @@ solana program show --buffers --all
 
 ### Set a program's upgrade authority
 
-The program's upgrade authority must to be present to deploy a program. If no
+The program's upgrade authority must be present to deploy a program. If no
 authority is specified during program deployment, the default keypair is used as
 the authority. This is why redeploying a program in the steps above didn't
 require an authority to be explicitly specified.
@@ -232,6 +228,11 @@ Or after deployment and specifying the current authority:
 solana program set-upgrade-authority <PROGRAM_ADDRESS> --upgrade-authority <UPGRADE_AUTHORITY_SIGNER> --new-upgrade-authority <NEW_UPGRADE_AUTHORITY>
 ```
 
+By default, `set-upgrade-authority` requires a signature from the new authority. This behavior prevents a
+developer from giving upgrade authority to a key that they do not have access to. The
+`--skip-new-upgrade-authority-signer-check` option relaxes the signer check. This can be useful for situations
+where the new upgrade authority is an offline signer or a multisig.
+
 ### Immutable programs
 
 A program can be marked immutable, which prevents all further redeployments, by
@@ -256,12 +257,12 @@ solana program dump <ACCOUNT_ADDRESS> <OUTPUT_FILEPATH>
 ```
 
 The dumped file will be in the same as what was deployed, so in the case of a
-shared object, the dumped file will be a fully functional shared object. Note
+shared object (the program binary `.so`), the dumped file will be a fully functional shared object. Note
 that the `dump` command dumps the entire data space, which means the output file
 will have trailing zeros after the shared object's data up to `max_len`.
 Sometimes it is useful to dump and compare a program to ensure it matches a
-known program binary. The original program file can be zero-extended, hashed,
-and compared to the hash of the dumped file.
+known program binary. The dumped file can be zero-truncated, hashed,
+and compared to the hash of the original program file.
 
 ```bash
 $ solana dump <ACCOUNT_ADDRESS> dump.so
@@ -298,5 +299,7 @@ solana program deploy --program-id <PROGRAM_ADDRESS> --buffer <BUFFER_ADDRESS>
 ```
 
 Note, the buffer's authority must match the program's upgrade authority.
+During deployment, the buffer account's contents are copied into the program-data account and
+the buffer account is set to zero. The lamports from the buffer account are refunded to a spill account.
 
 Buffers also support `show` and `dump` just like programs do.