docs: authz client spec (#10136)

## Description

Ref: #9707

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

- Add `client.md` to module specification.
- Add `client.md` page to `authz` module spec.

---

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- [x] provided a link to the relevant issue or specification
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I have...

- [ ] 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
- [ ] reviewed content for thoroughness
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- [ ] tested instructions (if applicable)

docs/spec/SPEC-SPEC.md

@@ -34,6 +34,7 @@ following list is nonbinding and all files are optional.
 - `XX_end_block.md` - specify any end-block operations
 - `XX_hooks.md` - describe available hooks to be called by/from this module
 - `XX_events.md` - list and describe event tags used
+- `XX_client.md` - list and describe CLI commands and gRPC and REST endpoints
 - `XX_params.md` - list all module parameters, their types (in JSON) and examples
 - `XX_future_improvements.md` - describe future improvements of this module
 - `XX_appendix.md` - supplementary details referenced elsewhere within the spec

x/authz/client/cli/tx.go

@@ -179,7 +179,7 @@ Examples:
 
 func NewCmdRevokeAuthorization() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "revoke [grantee] [msg_type] --from=[granter]",
+		Use:   "revoke [grantee] [msg-type-url] --from=[granter]",
 		Short: "revoke authorization",
 		Long: strings.TrimSpace(
 			fmt.Sprintf(`revoke authorization from a granter to a grantee:
@@ -212,7 +212,7 @@ Example:
 
 func NewCmdExecAuthorization() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "exec [msg_tx_json_file] --from [grantee]",
+		Use:   "exec [tx-json-file] --from [grantee]",
 		Short: "execute tx on behalf of granter account",
 		Long: strings.TrimSpace(
 			fmt.Sprintf(`execute tx on behalf of granter account:

x/authz/spec/05_client.md

@@ -0,0 +1,172 @@
+<!--
+order: 5
+-->
+
+# Client
+
+## CLI
+
+A user can query and interact with the `authz` module using the CLI.
+
+### Query
+
+The `query` commands allow users to query `authz` state.
+
+```bash
+simd query authz --help
+```
+
+#### grants
+
+The `grants` command allows users to query grants for a granter-grantee pair. If the message type URL is set, it will select grants only for that message type.
+
+```bash
+simd query authz grants [granter-addr] [grantee-addr] [msg-type-url]? [flags]
+```
+
+Example:
+
+```bash
+simd query authz grants cosmos1.. cosmos1.. /cosmos.bank.v1beta1.MsgSend
+```
+
+Example Output:
+
+```bash
+grants:
+- authorization:
+    '@type': /cosmos.bank.v1beta1.SendAuthorization
+    spend_limit:
+    - amount: "100"
+      denom: stake
+  expiration: "2022-01-01T00:00:00Z"
+pagination: null
+```
+
+### Transactions
+
+The `tx` commands allow users to interact with the `authz` module.
+
+```bash
+simd tx authz --help
+```
+
+#### exec
+
+The `exec` command allows a grantee to execute a transaction on behalf of granter.
+
+```bash
+  simd tx authz exec [tx-json-file] --from [grantee] [flags]
+```
+
+Example:
+
+```bash
+simd tx authz exec tx.json --from=cosmos1..
+```
+
+#### grant
+
+The `grant` command allows a granter to grant an authorization to a grantee.
+
+```bash
+simd tx authz grant <grantee> <authorization_type="send"|"generic"|"delegate"|"unbond"|"redelegate"> --from <granter> [flags]
+```
+
+Example:
+
+```bash
+simd tx authz grant cosmos1.. send --spend-limit=100stake --from=cosmos1..
+```
+
+#### revoke
+
+The `revoke` command allows a granter to revoke an authorization from a grantee.
+
+```bash
+simd tx authz revoke [grantee] [msg-type-url] --from=[granter] [flags]
+```
+
+Example:
+
+```bash
+simd tx authz revoke cosmos1.. /cosmos.bank.v1beta1.MsgSend --from=cosmos1..
+```
+
+## gRPC
+
+A user can query the `authz` module using gRPC endpoints.
+
+### Grants
+
+The `Grants` endpoint allows users to query grants for a granter-grantee pair. If the message type URL is set, it will select grants only for that message type.
+
+```bash
+cosmos.authz.v1beta1.Query/Grants
+```
+
+Example:
+
+```bash
+grpcurl -plaintext \
+    -d '{"granter":"cosmos1..","grantee":"cosmos1..","msg_type_url":"/cosmos.bank.v1beta1.MsgSend"}' \
+    localhost:9090 \
+    cosmos.authz.v1beta1.Query/Grants
+```
+
+Example Output:
+
+```bash
+{
+  "grants": [
+    {
+      "authorization": {
+        "@type": "/cosmos.bank.v1beta1.SendAuthorization",
+        "spendLimit": [
+          {
+            "denom":"stake",
+            "amount":"100"
+          }
+        ]
+      },
+      "expiration": "2022-01-01T00:00:00Z"
+    }
+  ]
+}
+```
+
+## REST
+
+A user can query the `authz` module using REST endpoints.
+
+```bash
+/cosmos/authz/v1beta1/grants
+```
+
+Example:
+
+```bash
+curl "localhost:1317/cosmos/authz/v1beta1/grants?granter=cosmos1..&grantee=cosmos1..&msg_type_url=/cosmos.bank.v1beta1.MsgSend"
+```
+
+Example Output:
+
+```bash
+{
+  "grants": [
+    {
+      "authorization": {
+        "@type": "/cosmos.bank.v1beta1.SendAuthorization",
+        "spend_limit": [
+          {
+            "denom": "stake",
+            "amount": "100"
+          }
+        ]
+      },
+      "expiration": "2022-01-01T00:00:00Z"
+    }
+  ],
+  "pagination": null
+}
+```

x/authz/spec/README.md

@@ -25,3 +25,7 @@ granting arbitrary privileges from one account (the granter) to another account
     - [MsgExec](03_messages.md#MsgExec)
 4. **[Events](04_events.md)**
     - [Keeper](04_events.md#Keeper)
+5. **[Client](05_client.md)**
+    - [CLI](05_client.md#cli)
+    - [gRPC](05_client.md#grpc)
+    - [REST](05_client.md#rest)