Pricing: mention custom domain limitations (#305)

We agreed on:

- 2 domains per project on community
- 5 domains per organization on Advanced
- 15 domains per organization on Pro

This is the first step: update our pricing page for new customer.
One of the next steps involves enforcing this in our application by adding Read
the Docs features to the plans and also showing the domains left in the admin.

Related readthedocs/readthedocs-corporate#1808

content/pages/pricing.html

@@ -57,7 +57,7 @@ <h1 class="ui medium header">
             <div class="ui list relaxed divided">
               {{ pricing.plan_feature("<em>Includes all <b>Basic plan</b> features</em>", "<a href='#compare'>Compare plan features</a>", "fa-object-intersect", color="violet") }}
               {{ pricing.plan_feature("Concurrent builds", "4 concurrent builds", "fa-rectangle-vertical-history fa-swap-opacity") }}
-              {{ pricing.plan_feature("Custom domains", "Use your own domain", "fa-at") }}
+              {{ pricing.plan_feature("Custom domains", "5 custom domains", "fa-at") }}
               {{ pricing.plan_feature("Search and pageview analytics", "30 day retention", "fa-line-chart") }}
             </div>
           {% endcall %}
@@ -70,6 +70,7 @@ <h1 class="ui medium header">
             <div class="ui list relaxed divided">
               {{ pricing.plan_feature("<em>Includes all <b>Advanced plan</b> features</em>", "<a href='#compare'>Compare plan features</a>", "fa-object-intersect", color="violet") }}
               {{ pricing.plan_feature("Concurrent builds", "6 concurrent builds", "fa-rectangle-vertical-history fa-swap-opacity") }}
+              {{ pricing.plan_feature("Custom domains", "15 custom domains", "fa-at") }}
               {{ pricing.plan_feature("Support", "1 business day response", "fa-message-question") }}
               {{ pricing.plan_feature("Search and pageview analytics", "90 day retention", "fa-line-chart") }}
               {{ pricing.plan_feature("Authentication auditing", "90 day retention", "fa-user-check") }}
@@ -127,7 +128,7 @@ <h2 class="ui small monospace center aligned header">
                   {{ pricing.plan_feature("Concurrent builds", "2 concurrent builds", "fa-rectangle-vertical-history fa-swap-opacity") }}
                   {{ pricing.plan_feature("Public projects", "Host public documentation", "fa-globe") }}
                   {{ pricing.plan_feature("Public repositories", "Clone public repositories", "fa-globe") }}
-                  {{ pricing.plan_feature("Custom domain", "Use your own domain", "fa-at") }}
+                  {{ pricing.plan_feature("Custom domain", "2 custom domains", "fa-at") }}
                   {{ pricing.plan_feature("Ad supported", "Hosted documentation includes ads", "fa-ad") }}
                 </div>
               </div>
@@ -243,7 +244,7 @@ <h3 class="ui small header">
       {{ pricing.feature_row("Single sign-on", "Sign on with using external provider", "fa-right-to-bracket", on_community=None, on_basic="GitHub and GitLab", on_advanced="GitHub and GitLab", on_pro=("GitHub, GitLab, and Google", "olive")) }}
       {{ pricing.feature_row("Sharing", "Provide temporary access to private documentation", "fa-user-shield", on_community=False) }}
       {{ pricing.feature_row("CDN hosting", "Reduce load times for your projects", "fa-clouds", on_community=True, on_basic="Public projects only", on_advanced="Public projects only", on_pro="Public projects only") }}
-      {{ pricing.feature_row("Custom domains", "Host projects on custom domain name", "fa-at", on_basic=False) }}
+      {{ pricing.feature_row("Custom domains", "Host projects on your own custom domain names", "fa-at", on_community="2", on_basic=False, on_advanced="5", on_pro="15") }}
       {{ pricing.feature_row("Subprojects", "Organize projects using project nesting", "fa-diagram-nested") }}
       {{ pricing.feature_row("Integrated search", "Search across all of your projects", "fa-magnifying-glass") }}
       {{ pricing.feature_row("Offline formats", "Download offline PDF and EPUB formats", "fa-file-pdf") }}