docs: remove cost, document missing options and improve docs (#653)

Author: lowlighter

.github/quickstart/plugin/metadata.yml

@@ -1,5 +1,4 @@
 name: "🧩 <%= `${name.charAt(0).toLocaleUpperCase()}${name.substring(1)}` %>"
-cost: Estimates how many GitHub requests is used during plugin execution ("N/A" for Third-Party services)
 category: other   # Set plugin category ("github", "social" or "other")
 supports:
   - user          # Support users account

.github/readme/partials/documentation/compatibility.md

@@ -10,7 +10,7 @@
   <tr>
     <td nowrap="nowrap"><%- name %></td><%# -%>
     <% for (const [plugin] of Object.entries(plugins).filter(([key, value]) => (value)&&(!["core"].includes(key)))) { %>
-    <td nowrap="nowrap" align="center" data-plugin="<%= plugin %>"><%= readme.compatibility[plugin] ? "✔️" : "❌" %></td><% } %>
+    <td nowrap="nowrap" align="center" data-plugin="<%= plugin %>"><%= {true:"✔️", false:"❌", embed:"✓"}[readme.compatibility[plugin]] %></td><% } %>
   </tr><% } %>
   <tr>
     <td colspan="<%= Object.keys(plugins).length %>"></td>