docs: add deep links (#5493)

* add deep links

* Update docs/en/index.md

Co-authored-by: Alexandre Alapetite <alexandre@alapetite.fr>

---------

Co-authored-by: Alexandre Alapetite <alexandre@alapetite.fr>

docs/en/index.md

@@ -10,16 +10,16 @@ FreshRSS has a lot of features including:
 
 * RSS and Atom aggregation
 * Mark article as favorite if you liked it or if you want to read it later
-* Filter and search functionality helps to easily find articles
+* Filter and search functionality helps to easily find articles ([more information](./users/10_filter.html))
 * Statistics to show you the publishing frequency all the websites you follow
-* Import/export of your feeds into OPML format
-* Several themes created by the community
-* Several extensions created by the community
-* "Google Reader"-like API to connect Android applications
+* Import/export of your feeds into OPML format ([more information](./users/04_Subscriptions.html#import--export))
+* Several themes created by the community ([more information](./admins/11_Themes.html))
+* Several extensions created by the community ([more information](./admins/15_extensions.html))
+* "Google Reader"-like API to connect Android applications ([more information](./users/06_Mobile_access.html#access-via-mobile-app))
 * The application is "responsive," which means it adapts to small screens so you can bring articles in your pocket
-* Self-hosted: the code is free (under AGPL3 licence), so you can host your own instance of FreshRSS
-* Multi-user, so you can also host for your friends and family
-* share article links with a bunch of services
+* Self-hosted: the code is free ([under AGPL3 licence](https://github.com/FreshRSS/FreshRSS/blob/edge/LICENSE.txt)), so you can host your own instance of FreshRSS ([more information](./admins/02_Prerequisites.md))
+* Multi-user, so you can also host for your friends and family ([more information](./admins/12_User_management.md))
+* share article links with a bunch of services ([more information](./users/08_sharing_services.md))
 * And a lot more!
 
 ## Manual Chapters
@@ -44,4 +44,4 @@ Another chance to try out, but not official supported by FreshRSS: The applicati
 
 ## Licence
 
-FreshRSS is licensed under the GNU Affero General Public License v3.0.
+FreshRSS is licensed under the [GNU Affero General Public License v3.0](https://github.com/FreshRSS/FreshRSS/blob/edge/LICENSE.txt).