Clarify which token should be used to delete a runner

CHANGELOG

@@ -483,6 +483,7 @@ v 8.11.0
   - Add pipeline events hook
   - Bump gitlab_git to speedup DiffCollection iterations
   - Rewrite description of a blocked user in admin settings. (Elias Werberich)
+  - Clarify documentation for Runners API (Gennady Trafimenkov)
   - Make branches sortable without push permission !5462 (winniehell)
   - Check for Ci::Build artifacts at database level on pipeline partial
   - Convert image diff background image to CSS (ClemMakesApps)

doc/api/ci/runners.md

@@ -12,7 +12,9 @@ communication channel. For the consumer API see the
 This API uses two types of authentication:
 
 1. Unique Runner's token, which is the token assigned to the Runner after it
-   has been registered.
+   has been registered.  This token can be found on the Runner's edit page (go to
+   **Project > Runners**, select one of the Runners listed under **Runners activated for
+   this project**).
 
 2. Using Runners' registration token.
    This is a token that can be found in project's settings.
@@ -48,7 +50,7 @@ DELETE /ci/api/v1/runners/delete
 
 | Attribute | Type    | Required  | Description |
 | --------- | ------- | --------- | ----------- |
-| `token`   | string  | yes       | Runner's registration token |
+| `token`   | string  | yes       | Unique Runner's token |
 
 Example request: