Rework Token API comments (#15162)

Move the token API discussion into a common section discussing the
generation and listing of the tokens.  Add a note on the display of
the sha1 during creation and listing.

Co-authored-by: Norwin <noerw@users.noreply.github.com>

docs/content/doc/developers/api-usage.en-us.md

@@ -40,8 +40,42 @@ better understand this by looking at the code -- as of this writing,
 Gitea parses queries and headers to find the token in
 [modules/auth/auth.go](https://github.com/go-gitea/gitea/blob/6efdcaed86565c91a3dc77631372a9cc45a58e89/modules/auth/auth.go#L47).
 
-You can create an API key token via your Gitea installation's web interface:
-`Settings | Applications | Generate New Token`.
+## Generating and listing API tokens
+
+A new token can be generated with a `POST` request to
+`/users/:name/tokens`.
+
+Note that `/users/:name/tokens` is a special endpoint and requires you
+to authenticate using `BasicAuth` and a password, as follows:
+
+
+```sh
+$ curl -XPOST -H "Content-Type: application/json"  -k -d '{"name":"test"}' -u username:password https://gitea.your.host/api/v1/users/<username>/tokens
+{"id":1,"name":"test","sha1":"9fcb1158165773dd010fca5f0cf7174316c3e37d","token_last_eight":"16c3e37d"}
+```
+
+The ``sha1`` (the token) is only returned once and is not stored in
+plain-text.  It will not be displayed when listing tokens with a `GET`
+request; e.g.
+
+```sh
+$ curl --request GET --url https://yourusername:password@gitea.your.host/api/v1/users/<username>/tokens
+[{"name":"test","sha1":"","token_last_eight:"........":},{"name":"dev","sha1":"","token_last_eight":"........"}]
+```
+
+To use the API with basic authentication with two factor authentication
+enabled, you'll need to send an additional header that contains the one
+time password (6 digitrotating token).
+An example of the header is `X-Gitea-OTP: 123456` where `123456`
+is where you'd place the code from your authenticator.
+Here is how the request would look like in curl:
+
+```sh
+$ curl -H "X-Gitea-OTP: 123456" --request GET --url https://yourusername:yourpassword@gitea.your.host/api/v1/users/yourusername/tokens
+```
+
+You can also create an API key token via your Gitea installation's web
+interface: `Settings | Applications | Generate New Token`.
 
 ## OAuth2 Provider
 
@@ -82,26 +116,6 @@ or on
 The OpenAPI document is at:
 `https://gitea.your.host/swagger.v1.json`
 
-## Listing your issued tokens via the API
-
-As mentioned in
-[#3842](https://github.com/go-gitea/gitea/issues/3842#issuecomment-397743346),
-`/users/:name/tokens` is special and requires you to authenticate
-using BasicAuth, as follows:
-
-### Using basic authentication:
-
-```sh
-$ curl --request GET --url https://yourusername:yourpassword@gitea.your.host/api/v1/users/yourusername/tokens
-[{"name":"test","sha1":"..."},{"name":"dev","sha1":"..."}]
-```
-
-As of v1.8.0 of Gitea, if using basic authentication with the API and your user has two factor authentication enabled, you'll need to send an additional header that contains the one time password (6 digit rotating token). An example of the header is `X-Gitea-OTP: 123456` where `123456` is where you'd place the code from your authenticator. Here is how the request would look like in curl:
-
-```sh
-$ curl -H "X-Gitea-OTP: 123456" --request GET --url https://yourusername:yourpassword@gitea.your.host/api/v1/users/yourusername/tokens
-```
-
 ## Sudo
 
 The API allows admin users to sudo API requests as another user. Simply add either a `sudo=` parameter or `Sudo:` request header with the username of the user to sudo.