docs/*: Fix codespell issues

See,
$ codespell -S './src/img/*.png,./.git*' -L que

Signed-off-by: Mario Trangoni <mjtrangoni@gmail.com>

docs/sources/configuration/index.md

@@ -56,7 +56,7 @@ Direct access is still supported because in some cases it may be useful to acces
 
 Direct DB Connection allows plugin to use existing SQL data source for querying history data directly from Zabbix
 database. This way usually faster than pulling data from Zabbix API, especially on the wide time ranges, and reduces
-amount of data transfered.
+amount of data transferred.
 
 Read [how to configure](./sql_datasource) SQL data source in Grafana.
 

docs/sources/guides/gettingstarted.md

@@ -25,7 +25,7 @@ Another case to use regex is comparing the same metrics for different hosts. Use
 ![Backend system time](../img/getstarting-regex_backend_system_time.png)
 
 ## Bar Chart
-Let's create a graph wich show queries stats for MySQL database. Select Group, Host, Application (_MySQL_ in my case) and Items. I use `/MySQL .* operations/` regex for filtering different types of operations.
+Let's create a graph which show queries stats for MySQL database. Select Group, Host, Application (_MySQL_ in my case) and Items. I use `/MySQL .* operations/` regex for filtering different types of operations.
 
 ![MySQL operations 1](../img/getstarting-mysql_operations_1.png)
 

docs/sources/reference/alerting.md

@@ -14,7 +14,7 @@ consists of two main parts:
 
 - **Alerting execution engine**  
     The alert rules are evaluated in the Grafana backend in a scheduler and query execution engine that is part of core 
-    Grafana. Only some data soures are supported right now. They include Graphite, Prometheus, InfluxDB and OpenTSDB.
+    Grafana. Only some data sources are supported right now. They include Graphite, Prometheus, InfluxDB and OpenTSDB.
 - **Alerting visualisations**  
     Alerts highlight panels with problems and it can easily be found on the dashboard.