static/frontend/unit: unit page title includes full path

To improve the titles of unit pages and keep them consistent with how
we display search results on pkgsite, the HTML title now includes the
full path to the unit.

Change-Id: I2d7939be243b04e3283db2212fa095e5dd9008ee
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/341866
Trust: Jamal Carvalho <jamal@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
Run-TryBot: Jamal Carvalho <jamal@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
diff --git a/static/frontend/unit/unit.tmpl b/static/frontend/unit/unit.tmpl
index f0c9171..364e190 100644
--- a/static/frontend/unit/unit.tmpl
+++ b/static/frontend/unit/unit.tmpl
@@ -4,7 +4,7 @@
   license that can be found in the LICENSE file.
 -->
 
-{{define "title"}}<title>{{.Title}} · pkg.go.dev</title>{{end}}
+{{define "title"}}<title>{{.Title}} · {{.Unit.Path}} · pkg.go.dev</title>{{end}}
 
 {{define "description"}}{{.MetaDescription}}{{end}}