docs: encode/decode transaction (#10133)

## Description

Closes: #10102

<!-- Add a description of the changes that this PR introduces and the files that
are the most critical to review. -->

Adds examples for encoding/decoding a transaction using the CLI. Also fixes CLI use and description.

---

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- [ ] included the correct `docs:` prefix in the PR title
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- [ ] provided a link to the relevant issue or specification
- [ ] followed the [documentation writing guidelines](https://github.com/cosmos/cosmos-sdk/blob/master/docs/DOC_WRITING_GUIDELINES.md)
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- [ ] confirmed the correct `docs:` prefix in the PR title
- [ ] confirmed all author checklist items have been addressed 
- [ ] confirmed that this PR only changes documentation
- [ ] reviewed content for consistency
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- [ ] tested instructions (if applicable)

x/auth/client/cli/decode.go

@@ -16,7 +16,7 @@ const flagHex = "hex"
 // it into a JSON-encoded transaction.
 func GetDecodeCommand() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "decode [amino-byte-string]",
+		Use:   "decode [protobuf-byte-string]",
 		Short: "Decode a binary encoded transaction string",
 		Args:  cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) (err error) {

x/auth/client/cli/encode.go

@@ -17,7 +17,7 @@ func GetEncodeCommand() *cobra.Command {
 		Use:   "encode [file]",
 		Short: "Encode transactions generated offline",
 		Long: `Encode transactions created with the --generate-only flag and signed with the sign command.
-Read a transaction from <file>, serialize it to the Amino wire protocol, and output it as base64.
+Read a transaction from <file>, serialize it to the Protobuf wire protocol, and output it as base64.
 If you supply a dash (-) argument in place of an input filename, the command reads from standard input.`,
 		Args: cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {