fix: Use Docs.HTML instead of Documenter.HTML for inline scripts

The `HTML` type imported from `Documenter` is the format specification
type (for configuring HTML output), not for embedding inline HTML content.

MultiDocumenter's `custom_scripts` parameter expects `Docs.HTML` from
Julia's standard library for inline script content.

Fixes build error:
  MethodError: no method matching HTML(::String)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: claude

docs/make_aggregate.jl

@@ -1,4 +1,4 @@
-using Documenter: Documenter, HTML
+using Documenter: Documenter
 using LibGit2
 using Pkg
 using MultiDocumenter
@@ -256,7 +256,7 @@ MultiDocumenter.make(
     ),
     custom_scripts = [
         "https://www.googletagmanager.com/gtag/js?id=G-Q3FE4BYYHQ",
-        HTML(
+        Docs.HTML(
             """
             window.dataLayer = window.dataLayer || [];
             function gtag(){dataLayer.push(arguments);}