static/shared: update go.dev solutions links to subpages

Update case studies and use cases links from go.dev/solutions#... to
go.dev/solutions/... to match the current go.dev navigation and avoid
relying on the /solutions/ redirect.

For golang/go#81341

Change-Id: If821f4d970e1457fdf261667c63a8ef1d3290897
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/827264
kokoro-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ethan Lee <ethanalee@google.com>

static/shared/footer/footer.tmpl

diff --git a/static/shared/footer/footer.tmpl b/static/shared/footer/footer.tmpl
index a5d5a05..013ee09 100644
--- a/static/shared/footer/footer.tmpl
+++ b/static/shared/footer/footer.tmpl
@@ -13,11 +13,11 @@
             data-gtmc="footer link">
           Why Go
         </a>
-        <a href="https://go.dev/solutions#use-cases" class="go-Footer-link"
+        <a href="https://go.dev/solutions/use-cases" class="go-Footer-link"
             data-gtmc="footer link">
           Use Cases
         </a>
-        <a href="https://go.dev/solutions#case-studies" class="go-Footer-link"
+        <a href="https://go.dev/solutions/case-studies" class="go-Footer-link"
             data-gtmc="footer link">
           Case Studies
         </a>

static/shared/header/header.tmpl

diff --git a/static/shared/header/header.tmpl b/static/shared/header/header.tmpl
index becb861..5eb985f 100644
--- a/static/shared/header/header.tmpl
+++ b/static/shared/header/header.tmpl
@@ -26,7 +26,7 @@
               <ul class="go-Header-submenu go-Header-submenu--why js-desktop-submenu-hover" aria-label="submenu">
                   <li class="go-Header-submenuItem">
                     <div>
-                      <a href="https://go.dev/solutions#case-studies">
+                      <a href="https://go.dev/solutions/case-studies">
                         <span>Case Studies</span>
                       </a>
                     </div>
@@ -34,7 +34,7 @@
                   </li>
                   <li class="go-Header-submenuItem">
                     <div>
-                      <a href="https://go.dev/solutions#use-cases">
+                      <a href="https://go.dev/solutions/use-cases">
                         <span>Use Cases</span>
                       </a>
                     </div>
@@ -247,12 +247,12 @@
                 </div>
                 <ul class="go-NavigationDrawer-list">
                   <li class="go-NavigationDrawer-listItem">
-                    <a href="https://go.dev/solutions#case-studies">
+                    <a href="https://go.dev/solutions/case-studies">
                       Case Studies
                     </a>
                   </li>
                   <li class="go-NavigationDrawer-listItem">
-                    <a href="https://go.dev/solutions#use-cases">
+                    <a href="https://go.dev/solutions/use-cases">
                       Use Cases
                     </a>
                   </li>