content,internal/frontend: use consistent casing for standard library

"Standard library" is also cased with a lowercase "library" throughout
the site. Previously, some parts of the site displayed "Standard
Library".

Change-Id: I41e1ff411f19ebd592991c39edaed68534cf8dc1
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/259205
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Julie Qiu <julie@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
diff --git a/content/static/html/helpers/_imports.tmpl b/content/static/html/helpers/_imports.tmpl
index 7fa1da4..a535761 100644
--- a/content/static/html/helpers/_imports.tmpl
+++ b/content/static/html/helpers/_imports.tmpl
@@ -24,7 +24,7 @@
         </ul>
       {{end}}
       {{if .StdLib}}
-        <h2 class="Imports-heading">Standard Library Imports</h2>
+        <h2 class="Imports-heading">Standard library Imports</h2>
         <ul class="Imports-list">
         {{range .StdLib}}
           <li><a href="/{{.}}">{{.}}</a></li>
diff --git a/content/static/html/pages/overview.tmpl b/content/static/html/pages/overview.tmpl
index fe6f3fe..bbbc374 100644
--- a/content/static/html/pages/overview.tmpl
+++ b/content/static/html/pages/overview.tmpl
@@ -8,8 +8,8 @@
   <div class="Overview">
     <div class="Overview-module">
       {{if eq .ModulePath "std"}}
-        <h2>Standard Library</h2>
-        <a href="{{.ModuleURL}}">Standard Library</a>
+        <h2>Standard library</h2>
+        <a href="{{.ModuleURL}}">Standard library</a>
       {{else}}
         <h2>Module</h2>
         <a href="{{.ModuleURL}}">{{.ModulePath}}</a>
diff --git a/internal/frontend/server_test.go b/internal/frontend/server_test.go
index f128eb9..5857d2f 100644
--- a/internal/frontend/server_test.go
+++ b/internal/frontend/server_test.go
@@ -517,7 +517,7 @@
 			want: in("",
 				pagecheck.PackageHeader(pkgV100, versioned),
 				in("[role='tab'][aria-selected='true']", text(`Imports`)),
-				in(".Imports-heading", text(`Standard Library Imports`)),
+				in(".Imports-heading", text(`Standard library Imports`)),
 				in(".Imports-list",
 					in("li:nth-child(1) a", href("/fmt"), text("fmt")),
 					in("li:nth-child(2) a", href("/path/to/bar"), text("path/to/bar")))),
@@ -648,7 +648,7 @@
 				pagecheck.DirectoryHeader(dirCmd, versioned),
 				pagecheck.OverviewDetails(&pagecheck.Overview{
 					ModuleLink:     "/std@go1.13",
-					ModuleLinkText: "Standard Library",
+					ModuleLinkText: "Standard library",
 					ReadmeContent:  "readme",
 					RepoURL:        "https://" + sample.ModulePath, // wrong, but hard to change
 					ReadmeSource:   "go.googlesource.com/go/+/refs/tags/go1.13/README.md",
diff --git a/internal/frontend/unit.go b/internal/frontend/unit.go
index b5dbebf..67161d3 100644
--- a/internal/frontend/unit.go
+++ b/internal/frontend/unit.go
@@ -330,7 +330,7 @@
 func displayBreadcrumb(unit *internal.Unit, requestedVersion string) breadcrumb {
 	bc := breadcrumbPath(unit.Path, unit.ModulePath, requestedVersion)
 	if unit.ModulePath == stdlib.ModulePath && unit.Path != stdlib.ModulePath {
-		bc.Links = append([]link{{Href: "/std", Body: "Standard Library"}}, bc.Links...)
+		bc.Links = append([]link{{Href: "/std", Body: "Standard library"}}, bc.Links...)
 	}
 	bc.Links = append([]link{{Href: "/", Body: "Discover Packages"}}, bc.Links...)
 	return bc