internal/frontend: handle emph and strong in rewriteLinks

For golang/go#61399

Change-Id: Iaf9be9ccd4d9deef61750b50ce3ea7699cf3c16b
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/548216
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>
diff --git a/internal/frontend/markdown.go b/internal/frontend/markdown.go
index 98072e3..50bfc85 100644
--- a/internal/frontend/markdown.go
+++ b/internal/frontend/markdown.go
@@ -273,10 +273,16 @@
 				x.URL = d
 			}
 		case *markdown.Image:
+			g.rewriteLinksInline(x.Inner)
 			if d := translateLink(x.URL, g.info, true, g.readme); d != "" {
 				x.URL = d
 			}
+		case *markdown.Emph:
+			g.rewriteLinksInline(x.Inner)
+		case *markdown.Strong:
+			g.rewriteLinksInline(x.Inner)
 		}
+
 	}
 }
 
diff --git a/internal/frontend/readme_test.go b/internal/frontend/readme_test.go
index df162c4..91b4b3e 100644
--- a/internal/frontend/readme_test.go
+++ b/internal/frontend/readme_test.go
@@ -469,6 +469,16 @@
 				{Level: 1, Text: "A link link", ID: "readme-a-link-link"},
 			},
 		},
+		{
+			name: "rewritten link in emph",
+			unit: unit,
+			readme: &internal.Readme{
+				Filepath: "README.md",
+				Contents: `**![alt](https://github.com/gobuffalo/buffalo/blob/master/logo.svg)**`,
+			},
+			wantHTML:    `<p><strong><img src="https://github.com/gobuffalo/buffalo/raw/master/logo.svg" alt="alt"/></strong></p>`,
+			wantOutline: nil,
+		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
 			processReadmes := map[string]func(ctx context.Context, u *internal.Unit) (frontendReadme *Readme, err error){