Docs: Fixed broken links in Basic Concepts (#21035)

* Fixed broken links

* Update basic_concepts.md

* Fix REF_NOT_FOUND errors

* add shortcode

Co-authored-by: Robby Milo <robbymilo@gmail.com>

docs/sources/features/datasources/_index.md

@@ -38,4 +38,4 @@ The following data sources are officially supported:
 
 ## Data source plugins
 
-Since grafana 3.0 you can install data sources as plugins. Check out [Grafana.net](https://grafana.com/plugins) for more data sources.
+Since Grafana 3.0 you can install data sources as plugins. Check out [Grafana.net](https://grafana.com/plugins) for more data sources.

docs/sources/installation/debian.md

@@ -15,7 +15,7 @@ weight = 200
 
 This page explains how to install Grafana dependencies, download and install Grafana, get the service up and running on your system, and the package details.
 
-**Note on upgrading:** While the process for upgrading Grafana is very similar to installing Grafana, there are some key backup steps you should perform. Read [Upgrading Grafana]({{< relref "installation/upgrading.md" >}}) for tips and guidance on updating an existing installation.
+**Note on upgrading:** While the process for upgrading Grafana is very similar to installing Grafana, there are some key backup steps you should perform. Read [Upgrading Grafana]({{< relref "upgrading.md" >}}) for tips and guidance on updating an existing installation.
 
 ## 1. Download and install