fix readme view bug (#2566)

Author: lunny

routers/repo/view.go

@@ -200,8 +200,10 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 		ctx.Data["IsMarkup"] = isSupportedMarkup
 		readmeExist := markup.IsReadmeFile(blob.Name())
 		ctx.Data["ReadmeExist"] = readmeExist
-		if readmeExist && isSupportedMarkup {
+		if isSupportedMarkup {
 			ctx.Data["FileContent"] = string(markup.Render(blob.Name(), buf, path.Dir(treeLink), ctx.Repo.Repository.ComposeMetas()))
+		} else if readmeExist {
+			ctx.Data["FileContent"] = string(bytes.Replace(buf, []byte("\n"), []byte(`<br>`), -1))
 		} else {
 			// Building code view blocks with line number on server side.
 			var fileContent string