docs(a11y): add alt texts to images + minor rewording

website/docs/integrations/jira-server-plugin-installation.md

@@ -43,13 +43,13 @@ The [Jira server plugin is available in the Atlassian marketplace](https://marke
 After the plugin is installed. Jira's Manage Apps page will have a new menu section called "Unleash Admin" with a single
 link - "Configure servers".
 
-![Jira Manage Apps - Unleash Admin](/img/jira_server_manage_unleash_admin.png)
+![The "configure servers" link highlighted in the Manage Apps menu.](/img/jira_server_manage_unleash_admin.png)
 
 Following the "Configure servers" link will take you to a config page where you can setup your connection(s) to Unleash
 servers. The Unleash Jira server plugin supports having a global server configured for all Jira projects, or a specific
 server configured for a specific Jira project.
 
-![Jira Manage Apps - Unleash Server Admin](/img/jira_server_manage_servers.png)
+![A table marked Unleash Server Configuration, listing Unleash server instances.](/img/jira_server_manage_servers.png)
 
 Once you have configured at least one Unleash server, your users should be ready to [use the Jira Server plugin](/integrations/jira_server_plugin_usage)
 
@@ -58,7 +58,7 @@ Once you have configured at least one Unleash server, your users should be ready
 In the list of known servers, each server has a connected edit button. Clicking the edit button brings up the edit
 dialog for the server, allowing you to change the details for the selected server
 
-![Jira Manage Apps - Edit server](/img/jira_server_edit_server.png)
+![An "editing server" form. The fields are "JIRA project", "Name", "Api URL", "Api Key"](/img/jira_server_edit_server.png)
 
 
 ### Delete (disconnect) existing servers
@@ -67,9 +67,9 @@ Deleting a server from the admin interface does not actually delete the server,
 server.
 Since this is a destructive operation, our plugin will ask for confirmation that you're sure you want to do this.
 
-![Jira Manage apps - Delete server confirmation](/img/jira_server_delete_server_confirmation.png)
+![A plugin deletion confirmation dialog. It gives you two options: "Delete connection", and "Cancel".](/img/jira_server_delete_server_confirmation.png)
 
-You will not be allowed to delete a server that has toggles connected to issues, instead you'll receive a
+You cannot delete a server that has toggles connected to issues. Instead, you'll get a
 warning dialog telling you that you'll need to disconnect the toggles from their issues first.
 
-![Jira Manage apps - Delete server connected toggles](/img/jira_server_delete_connected_toggles.png)
+![A warning dialog telling you that you can't delete a server.](/img/jira_server_delete_connected_toggles.png)