Improve control char rendering and escape button styling (#37094)

Follow-up to #37078.

- Use Unicode Control Pictures](U+2400-U+2421) to render C0 control characters
- Make it work in diff view too
- Replace escape warning emoji with SVG
- Align escape warning button with code lines

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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/repo/view.go

@@ -159,7 +159,7 @@ func markupRenderToHTML(ctx *context.Context, renderCtx *markup.RenderContext, r
 	go func() {
 		sb := &strings.Builder{}
 		if markup.RendererNeedPostProcess(renderer) {
-			escaped, _ = charset.EscapeControlReader(markupRd, sb, ctx.Locale, charset.RuneNBSP) // We allow NBSP here this is rendered
+			escaped, _ = charset.EscapeControlReader(markupRd, sb, ctx.Locale, charset.EscapeOptionsForView())
 		} else {
 			escaped = &charset.EscapeStatus{}
 			_, _ = io.Copy(sb, markupRd)

routers/web/repo/wiki.go

@@ -258,8 +258,7 @@ func renderViewPage(ctx *context.Context) (*git.Repository, *git.TreeEntry) {
 		defer markupWr.Close()
 		done := make(chan struct{})
 		go func() {
-			// We allow NBSP here this is rendered
-			escaped, _ = charset.EscapeControlReader(markupRd, buf, ctx.Locale, charset.RuneNBSP)
+			escaped, _ = charset.EscapeControlReader(markupRd, buf, ctx.Locale, charset.EscapeOptionsForView())
 			output = template.HTML(buf.String())
 			buf.Reset()
 			close(done)