Document 'object_attributes.action' for issue, MR, and release webhooks

Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/user/project/integrations/webhooks.md

@@ -112,7 +112,7 @@ branches, this hook isn't executed.
 X-Gitlab-Event: Push Hook
 ```
 
-**Request body:**
+**Payload example:**
 
 ```json
 {
@@ -202,7 +202,7 @@ tags, this hook is not executed.
 X-Gitlab-Event: Tag Push Hook
 ```
 
-**Request body:**
+**Payload example:**
 
 ```json
 {
@@ -256,7 +256,14 @@ Triggered when a new issue is created or an existing issue was updated/closed/re
 X-Gitlab-Event: Issue Hook
 ```
 
-**Request body:**
+**Available `object_attributes.action`:**
+
+- `open`
+- `close`
+- `reopen`
+- `update`
+
+**Payload example:**
 
 ```json
 {
@@ -423,7 +430,7 @@ Valid target types:
 X-Gitlab-Event: Note Hook
 ```
 
-**Request body:**
+**Payload example:**
 
 ```json
 {
@@ -505,7 +512,7 @@ X-Gitlab-Event: Note Hook
 X-Gitlab-Event: Note Hook
 ```
 
-**Request body:**
+**Payload example:**
 
 ```json
 {
@@ -634,7 +641,7 @@ X-Gitlab-Event: Note Hook
 X-Gitlab-Event: Note Hook
 ```
 
-**Request body:**
+**Payload example:**
 
 ```json
 {
@@ -742,7 +749,7 @@ NOTE:
 X-Gitlab-Event: Note Hook
 ```
 
-**Request body:**
+**Payload example:**
 
 ```json
 {
@@ -820,7 +827,17 @@ Triggered when a new merge request is created, an existing merge request was upd
 X-Gitlab-Event: Merge Request Hook
 ```
 
-**Request body:**
+**Available `object_attributes.action`:**
+
+- `open`
+- `close`
+- `reopen`
+- `update`
+- `approved`
+- `unapproved`
+- `merge`
+
+**Payload example:**
 
 ```json
 {
@@ -983,7 +1000,7 @@ Triggered when a wiki page is created, updated or deleted.
 X-Gitlab-Event: Wiki Page Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1044,7 +1061,7 @@ Triggered on status change of Pipeline.
 X-Gitlab-Event: Pipeline Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1291,7 +1308,7 @@ Triggered on status change of a job.
 X-Gitlab-Event: Job Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1370,7 +1387,7 @@ Triggered when a deployment:
 X-Gitlab-Event: Deployment Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1433,7 +1450,7 @@ Member events are triggered when:
 X-Gitlab-Event: Member Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1461,7 +1478,7 @@ X-Gitlab-Event: Member Hook
 X-Gitlab-Event: Member Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1489,7 +1506,7 @@ X-Gitlab-Event: Member Hook
 X-Gitlab-Event: Member Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1526,7 +1543,7 @@ Subgroup events are triggered when:
 X-Gitlab-Event: Subgroup Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1554,7 +1571,7 @@ X-Gitlab-Event: Subgroup Hook
 X-Gitlab-Event: Subgroup Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1587,7 +1604,7 @@ Triggered when a feature flag is turned on or off.
 X-Gitlab-Event: Feature Flag Hook
 ```
 
-**Request Body**:
+**Payload example**:
 
 ```json
 {
@@ -1637,7 +1654,12 @@ Triggered when a release is created or updated.
 X-Gitlab-Event: Release Hook
 ```
 
-**Request Body**:
+**Available `object_attributes.action`:**
+
+- `create`
+- `update`
+
+**Payload example**:
 
 ```json
 {