Style Schema Reference index-property-only types

TypeDoc generates a `.tsd-type-declaration` block as a direct child of
the `.type` wrapper for types with only index properties (e.g.,
`type Foo = { [key: string]: unknown }`). This differs from interface
members, which are nested inside `.tsd-member` elements.

Add CSS rules for `.type > .tsd-type-declaration` to hide the redundant
block when there are no doc comments, hide the templated "Type
Declaration" heading, and style the index property heading with
monospace font to match other member headings.

Author: jonathanhefner

docs/style.css

@@ -314,7 +314,7 @@ body:has(#schema-reference) {
 
     /* Sub-members */
     .tsd-type-declaration {
-      /* Templated heading */
+      /* Templated heading ("Type Declaration") */
       [data-typedoc-h="4"] {
         display: none;
       }
@@ -364,6 +364,25 @@ body:has(#schema-reference) {
       display: none;
     }
   }
+
+  /* Types with only index properties (e.g., `type Foo = { [key: string]: unknown }`) */
+  .type > .tsd-type-declaration {
+    /* Hide property if no doc comments */
+    &:not(:has(.tsd-comment)) {
+      display: none;
+    }
+
+    /* Templated heading ("Type Declaration") */
+    [data-typedoc-h="4"] {
+      display: none;
+    }
+
+    /* Index property */
+    [data-typedoc-h="5"] {
+      font-family: var(--font-mono);
+      font-weight: 700;
+    }
+  }
 }