Add a filename to anchor links in build docs.

The href base added by I8a8ac0f9ba6c0d57ed83db2155955a95e070a265
doesn't really play nice with anchor links. This fixes the issue.

Fixes: 126550408
Test: m soong_docs
Change-Id: If62411a6391fd8151fa40cb2ecf32c5006797d6c

cmd/soong_build/writedocs.go

@@ -241,7 +241,7 @@ li a:hover:not(.active) {
 {{- /* Fixed sidebar with module types */ -}}
 <ul>
 <li><h3>{{.Name}} package</h3></li>
-{{range $moduleType := .Modules}}<li><a href="#{{$moduleType.Name}}">{{$moduleType.Name}}</a></li>
+{{range $moduleType := .Modules}}<li><a href="{{$.Name}}.html#{{$moduleType.Name}}">{{$moduleType.Name}}</a></li>
 {{end -}}
 </ul>
 {{/* Main panel with H1 section per module type */}}
@@ -255,7 +255,7 @@ li a:hover:not(.active) {
 	<div class="breadcrumb">
     {{range $i,$prop := $moduleType.Properties }}
 				{{ if gt $i 0 }},&nbsp;{{end -}}
-				<a href=#{{getModule}}.{{$prop.Name}}>{{$prop.Name}}</a>
+				<a href={{$.Name}}.html#{{getModule}}.{{$prop.Name}}>{{$prop.Name}}</a>
 		{{- end -}}
   </div>
 	{{- /* Property description */ -}}