Fix some stale external links

content/blog/lektor-at-rails-girls-summer-of-code/contents.lr

@@ -32,9 +32,9 @@ website:
 > stipend, from July-September, to work on Open Source projects of their
 > choice.
 
-Lektor was accepted as a particpating project.  For more information about
+Lektor was accepted as a participating project.  For more information about
 the project there refer to the [project overview on
-RGSOC](https://teams.railsgirlssummerofcode.org/projects/115-lektor-cms).
+RGSOC :ext](https://railsgirlssummerofcode.org/blog/page/36/).
 
 We want to make it as easy as possible to work on Lektor during the event which
 is why we will be very flexible with regards to which area interested
@@ -44,3 +44,5 @@ If you are interested in working on Lektor you can reach out to us via
 Twitter at [@getlektor](https://twitter.com/getlektor) or
 <a href="https://gitter.im/lektor/lektor"
 class="js-gitter-toggle-chat-button">Gitter</a>.
+----
+class: default

content/docs/api/environment/jinja-env/contents.lr

@@ -7,7 +7,7 @@ summary: The configured Jinja 2 Environment.
 body:
 
 This object is a configured Jinja2 environment.  For more information you can
-refer to the [Jinja 2 Documentation :ref](http://jinja.pocoo.org/docs/dev/api/#jinja2.Environment).
+refer to the [Jinja 2 Documentation :ext](https://jinja.palletsprojects.com/en/3.0.x/api/#jinja2.Environment).
 
 This is where plugins can inject additional data like custom filters, tests
 or global functions.

content/docs/api/publisher/publish/contents.lr

@@ -20,7 +20,7 @@ The parameters to the function are as follows:
 
 * `target_url`: a URL object with the parsed URL.  This object comes from the
   Werkzeug library and gives access to the individual parts of a URL by the
-  exposed attributes ([Read about the URL object :ext](http://werkzeug.pocoo.org/docs/0.11/urls/)).
+  exposed attributes ([Read about the URL object :ext](https://werkzeug.palletsprojects.com/en/2.0.x/urls/)).
 * `credentials`: an optional dictionary with command line supplied credentials.
   Note that these credentials might be completely absent and the keys which are
   provided might change with future versions of Lektor.

content/docs/api/templates/filters/contents.lr

@@ -5,4 +5,4 @@ summary: Filters specific to Lektor that templates have access to.
 body:
 
 These is the list of custom filters added by Lektor in addition to the
-[built in filters :ext](http://jinja.pocoo.org/docs/dev/templates/#builtin-filters).
+[built in filters :ext](https://jinja.palletsprojects.com/en/3.0.x/templates/#list-of-builtin-filters).

content/docs/deployment/glpages/contents.lr

@@ -5,7 +5,7 @@ summary: Deploys to GitLab Pages.
 body:
 
 [GitLab](https://gitlab.com/) supports Lektor on their [GitLab
-Pages](http://doc.gitlab.com/ee/pages/) infrastructure.  Effectively
+Pages](https://docs.gitlab.com/ee/user/project/pages/) infrastructure.  Effectively
 GitLab can build your website out of any repository on GitLab and hosts it
 up on either a subdomain or a custom domain (including SSL).
 
@@ -90,7 +90,7 @@ pages:
 If you want to use a [CNAME :ext](https://en.wikipedia.org/wiki/CNAME) with
 GitLab pages you can configure it in the GitLab settings:
 
-* [Configure CNAME](http://doc.gitlab.com/ee/pages/#add-a-custom-domain-to-your-pages-website)
+* [Configure CNAME](https://docs.gitlab.com/ee/user/project/pages/custom_domains_ssl_tls_certification/#set-up-pages-with-a-custom-domain)
 
 ## SSL/TLS Support
 
@@ -98,7 +98,7 @@ If you have an SSL certificate and a custom domain, you can upload your private
 key and certificate to GitLab and SSL will become available on your custom
 domain as well.
 
-* [Configure SSL/TLS](http://doc.gitlab.com/ee/pages/#secure-your-custom-domain-website-with-tls)
+* [Configure SSL/TLS](https://docs.gitlab.com/ee/user/project/pages/custom_domains_ssl_tls_certification/#adding-an-ssltls-certificate-to-pages)
 
 ## 404 Pages
 

content/docs/plugins/dev/contents.lr

@@ -81,7 +81,7 @@ So going line by line, these are what the things mean:
   is your plugin name with underscores instead of dashes as separators.
   If you need more than one module you should use a package instead.  This is
   not covered here, but you can find this in the [setuptools documentation
-  :ext](https://pythonhosted.org/setuptools/).
+  :ext](https://setuptools.pypa.io/en/latest/).
 * `entry_points`: this is meta data that is needed to associate our package
   with Lektor.  Lektor will load all plugins in the `lektor.plugins` list.
   It can be a list of definitions in the form `plugin-name = import_path`.