SAML: change message when connecting account to SAML (#602)

Ref
readthedocs/readthedocs-corporate#1966 (comment)

![Screenshot 2025-05-27 at 16-17-45 Sign in - Read the Docs
Dev](https://github.com/user-attachments/assets/013a59b3-5687-49fc-82b5-7100ab2d6c2f)

Author: stsewd

readthedocsext/theme/templates/socialaccount/login.html

@@ -1,29 +1,47 @@
 {% extends "socialaccount/base_entrance.html" %}
 
-{% load i18n %}
+{% load trans blocktrans from i18n %}
+{% load crispy from crispy_forms_tags %}
 
-{% block head_title %}{% trans "Sign in" %}{% endblock %}
+{% block head_title %}
+  {% trans "Sign in" %}
+{% endblock head_title %}
 
-{% block content %}
+{% block content_title_text %}
   {% if process == "connect" %}
-    <h1>
-      {% blocktrans with provider.name as provider trimmed %}
-        Connect {{ provider }}
+    {% if provider.id == "saml" %}
+      {% blocktrans trimmed with organization_name=provider.organization.name %}
+        Switch account to SAML for {{ organization_name }}
       {% endblocktrans %}
-    </h1>
-
-    <p>
+    {% else %}
       {% blocktrans with provider.name as provider trimmed %}
-        You are about to connect a new third party account from {{ provider }}.
+        Connect {{ provider }}
       {% endblocktrans %}
-    </p>
+    {% endif %}
   {% else %}
-    <h1>
-      {% blocktrans with provider.name as provider trimmed %}
-        Sign in via {{ provider }}
-      {% endblocktrans %}
-    </h1>
+    {% blocktrans with provider.name as provider trimmed %}
+      Sign in via {{ provider }}
+    {% endblocktrans %}
+  {% endif %}
+{% endblock content_title_text %}
 
+{% block content_body %}
+  {% if process == "connect" %}
+    {% if provider.id == "saml" %}
+      <p>
+        {% blocktrans trimmed with organization_name=provider.organization.name %}
+          You are about to switch your account to use SAML to sign in to {{ organization_name }}.
+          After this, you will need to sign in using the "Single sign-on" option on the login page.
+        {% endblocktrans %}
+      </p>
+    {% else %}
+      <p>
+        {% blocktrans with provider.name as provider trimmed %}
+          You are about to connect a new third party account from {{ provider }}.
+        {% endblocktrans %}
+      </p>
+    {% endif %}
+  {% else %}
     <p>
       {% blocktrans with provider.name as provider trimmed %}
         You are about to sign in using a third party account from {{ provider }}.
@@ -33,6 +51,6 @@ <h1>
 
   <form method="post" class="ui form">
     {% csrf_token %}
-    <button class="ui button" type="submit">{% trans "Continue" %}</button>
+    <button class="ui primary button" type="submit">{% trans "Continue" %}</button>
   </form>
-{% endblock content %}
+{% endblock content_body %}