Fix header name from 'Authentication' to 'Authorization' (#700)

Author: maxwassiljew

docs/api/authenticated-endpoints.md

@@ -5,7 +5,7 @@ All endpoints under namespace `/api/v1/auth` require authentication.
 Authentication can be in one of two forms:
 
 - A `Cookie: <SID>` header (for logged in users)
-- An `Authentication: Bearer <TOKEN>` (recommended)
+- An `Authorization: Bearer <TOKEN>` (recommended)
 
 A new token can be generated from `/authorize_token` with the given parameters:
 
@@ -447,4 +447,4 @@ Returns 204 on success.
 
 Delete a video from the user watched history.
 
-Returns 204 on success.
+Returns 204 on success.