Fix typos in training documentation (#1782)

- Fix hhttps:// to https:// in training-schools.yml (line 80)

- Fix trainning-schools.yml to training-schools.yml in howto-website.md (line 92)

- Fix /workinggroups/training.html to /activities/training.html in howto-website.md (line 88)

Author: Rudra-Tiwari-codes

_data/training-schools.yml

@@ -77,7 +77,7 @@
   date: 2024-04-15
   deadline: ''
   end_date: 2024-04-19
-  source: hhttps://indico.cern.ch/event/1370034/
+  source: https://indico.cern.ch/event/1370034/
   tags: []
   title: First steps with Geant4
 - author: Sudhir Malik

howto-website.md

@@ -85,7 +85,7 @@ in there. The [Events](http://hepsoftwarefoundation.org/events.html) page and th
 ### Adding a training event
 
 For *training events* we have a special handling that lists all of these together on the 
-[Training Activity Area page]({{ site.baseurl }}/workinggroups/training.html). To create a new
+[Training Activity Area page]({{ site.baseurl }}/activities/training.html). To create a new
 entry you can either:
 
 1. Run the interactive script ``scripts/add_training_event.py`` (recommended)