Merge branch 'tc-api-v4-doc-changes' into 'master'

API v4 doc changes

See merge request !9723

doc/api/projects.md

@@ -20,7 +20,7 @@ Constants for project visibility levels are next:
 
 ## List projects
 
-Get a list of projects for which the authenticated user is a member.
+Get a list of visible projects for authenticated user. When being accessed without authentication, all public projects are returned.
 
 ```
 GET /projects

doc/api/v3_to_v4.md

 # V3 to V4 version
 
-Our V4 API version is currently available as *Beta*! It means that V3
-will still be supported and remain unchanged for now, but be aware that the following
-changes are in V4:
+Since GitLab 9.0, API V4 is the preferred version to be used.
+
+V3 will remain working until at least GitLab 9.3. The V3 API documentation is still [available](https://gitlab.com/gitlab-org/gitlab-ce/blob/8-16-stable/doc/api/README.md).
+
+Below are the changes made between V3 and V4.
 
 ### 8.17