Merge branch '3264-update-project-aliases-api-docs' into 'master'

Update Project Aliases API documentation

See merge request gitlab-org/gitlab-ce!30288

doc/api/project_aliases.md

@@ -69,12 +69,18 @@ POST /project_aliases
 ```
 
 | Attribute    | Type           | Required | Description                            |
-|--------------|--------|----------|-----------------------------------------------|
-| `project_id` | string | yes      | The ID or URL-encoded path of the project.    |
+|--------------|----------------|----------|----------------------------------------|
+| `project_id` | integer/string | yes      | The ID or path of the project.         |
 | `name`       | string         | yes      | The name of the alias. Must be unique. |
 
 ```
-curl --request POST "https://gitlab.example.com/api/v4/project_aliases" --form "project_id=gitlab-org%2Fgitlab-ee" --form "name=gitlab-ee"
+curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/project_aliases" --form "project_id=1" --form "name=gitlab-ee"
+```
+
+or
+
+```
+curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/project_aliases" --form "project_id=gitlab-org/gitlab-ee" --form "name=gitlab-ee"
 ```
 
 Example response: