content/static/html/helpers: change anchor links for sections

The top level sections now have anchor links in the format of
#section-<headingName>.

Change-Id: I9813e8ab226f3696ae09378ba3b560525664bfc1
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/259958
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Trust: Julie Qiu <julie@golang.org>
diff --git a/content/static/html/helpers/_unit_directories.tmpl b/content/static/html/helpers/_unit_directories.tmpl
index a0772c2..f14825b 100644
--- a/content/static/html/helpers/_unit_directories.tmpl
+++ b/content/static/html/helpers/_unit_directories.tmpl
@@ -5,7 +5,7 @@
 -->
 
 {{define "unit_directories"}}
-  <div class="UnitDirectories" id="directories-top">
+  <div class="UnitDirectories" id="section-directories">
     <h2 class="UnitDirectories-title">
       <img height="25px" width="20px" src="/static/img/pkg-icon-folder_20x16.svg">Directories
     </h2>
diff --git a/content/static/html/helpers/_unit_doc.tmpl b/content/static/html/helpers/_unit_doc.tmpl
index f50870e..4839015 100644
--- a/content/static/html/helpers/_unit_doc.tmpl
+++ b/content/static/html/helpers/_unit_doc.tmpl
@@ -5,7 +5,7 @@
 -->
 
 {{define "unit_doc"}}
-  <div class="UnitDoc" id="doc-top">
+  <div class="UnitDoc" id="section-documentation">
     <h2 class="UnitDoc-title">
       <img height="25px" width="20px" src="/static/img/pkg-icon-doc_20x12.svg">Documentation
     </h2>
diff --git a/content/static/html/helpers/_unit_files.tmpl b/content/static/html/helpers/_unit_files.tmpl
index 282e46e..e155579 100644
--- a/content/static/html/helpers/_unit_files.tmpl
+++ b/content/static/html/helpers/_unit_files.tmpl
@@ -5,7 +5,7 @@
 -->
 
 {{define "unit_files"}}
-  <div class="UnitFiles" id="files-top">
+  <div class="UnitFiles" id="section-sourcefiles">
     <h2 class="UnitFiles-title">
       <img height="16px" width="12px" src="/static/img/pkg-icon-file_16x12.svg">Source Files
     </h2>
diff --git a/content/static/html/helpers/_unit_outline.tmpl b/content/static/html/helpers/_unit_outline.tmpl
index 419b1b3..655ef11 100644
--- a/content/static/html/helpers/_unit_outline.tmpl
+++ b/content/static/html/helpers/_unit_outline.tmpl
@@ -12,7 +12,7 @@
       </button>
     </div>
     {{if .Readme.String}}
-      <a href="?readme=expanded#readme-top" class="UnitOutline-accordion js-accordionTrigger js-readmeExpand"
+      <a href="?readme=expanded#section-readme" class="UnitOutline-accordion js-accordionTrigger js-readmeExpand"
           role="button" aria-expanded="false" aria-controls="readme-panel" id="readme-accordion">
         README
       </a>
@@ -20,7 +20,7 @@
           id="readme-panel" role="region" aria-labelledby="readme-accordion" aria-hidden="true"></div>
     {{end}}
     {{if (or .DocOutline.String .Unit.IsPackage)}}
-      <a class="UnitOutline-accordion  js-accordionTrigger" href="#doc-top"
+      <a class="UnitOutline-accordion  js-accordionTrigger" href="#section-documentation"
           role="button" aria-expanded="false" aria-controls="outline-panel" id="outline-accordion">
         Documentation
       </a>
@@ -32,7 +32,7 @@
       </div>
     {{end}}
     {{if .SourceFiles}}
-      <a class="UnitOutline-accordion js-accordionTrigger" href="#files-top"
+      <a class="UnitOutline-accordion js-accordionTrigger" href="#section-sourcefiles"
           role="button" aria-expanded="false" aria-controls="files-panel" id="files-accordion">
         Source Files
       </a>
@@ -40,7 +40,7 @@
           id="files-panel" role="region" aria-labelledby="files-accordion" aria-hidden="true"></div>
     {{end}}
     {{if (or .Subdirectories .NestedModules)}}
-      <a class="UnitOutline-accordion js-accordionTrigger" href="#directories-top"
+      <a class="UnitOutline-accordion js-accordionTrigger" href="#section-directories"
           role="button" aria-expanded="false" aria-controls="directories-panel" id="directories-accordion">
         Directories
       </a>
diff --git a/content/static/html/helpers/_unit_readme.tmpl b/content/static/html/helpers/_unit_readme.tmpl
index 84acd97..0044555 100644
--- a/content/static/html/helpers/_unit_readme.tmpl
+++ b/content/static/html/helpers/_unit_readme.tmpl
@@ -5,7 +5,7 @@
 -->
 
 {{define "unit_readme"}}
-  <div class="UnitReadme {{if .ExpandReadme}}UnitReadme--expanded{{end}} js-readme" id="readme-top">
+  <div class="UnitReadme {{if .ExpandReadme}}UnitReadme--expanded{{end}} js-readme" id="section-readme">
     <h2 class="UnitReadme-title">
       <img height="25px" width="20px" src="/static/img/pkg-icon-readme_20x16.svg">README
     </h2>
@@ -14,8 +14,8 @@
         <div class="Overview-readmeContent">{{.Readme}}</div>
         <div class="UnitReadme-fadeOut"></div>
       </div>
-      <a class="UnitReadme-expandLink js-readmeExpand" href="?readme=expanded#readme-top">Expand ▾</a>
-      <a class="UnitReadme-collapseLink js-readmeCollapse" href="?#readme-top">Collapse ▴</a>
+      <a class="UnitReadme-expandLink js-readmeExpand" href="?readme=expanded#section-readme">Expand ▾</a>
+      <a class="UnitReadme-collapseLink js-readmeCollapse" href="?#section-readme">Collapse ▴</a>
     {{end}}
   </div>
 {{end}}