feat(RepoPage): add tip for submitting proposal

to encourage visitors to use ngit to submit a proposal

src/routes/repo/[repo_id]/+page.svelte

@@ -102,6 +102,32 @@
             proposals_or_issues={$proposal_summaries.summaries}
             loading={$proposal_summaries.loading}
           />
+          <div role="alert" class="alert mt-6">
+            <svg
+              xmlns="http://www.w3.org/2000/svg"
+              fill="none"
+              viewBox="0 0 24 24"
+              class="h-6 w-6 shrink-0 stroke-info"
+              ><path
+                stroke-linecap="round"
+                stroke-linejoin="round"
+                stroke-width="2"
+                d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z"
+              ></path></svg
+            >
+            <div>
+              <h3 class="prose mb-2 text-sm font-bold">
+                want to submit a proposal?
+              </h3>
+              <p class="prose text-xs">
+                <a href="/ngit">install ngit</a>, create add a feature in the
+                local repository and run
+                <span class="rounded bg-neutral p-1 font-mono"
+                  ><span class="py-3">ngit send</span></span
+                >
+              </p>
+            </div>
+          </div>
         {:else if selected_tab === 'issues'}
           <ProposalsList
             proposals_or_issues={$issue_summaries.summaries}