Refactor tmpl and blob_excerpt (#32967)

1. do not use `{{/* */}}` to remove spaces, use `{{- -}}`
2. fix "blob_excerpt" endpoint, remove the legacy fragile code: have
tested commit diff and wiki diff

routers/common/middleware.go

@@ -24,7 +24,7 @@ import (
 func ProtocolMiddlewares() (handlers []any) {
 	// the order is important
 	handlers = append(handlers, ChiRoutePathHandler())   // make sure chi has correct paths
-	handlers = append(handlers, RequestContextHandler()) //	// prepare the context and panic recovery
+	handlers = append(handlers, RequestContextHandler()) //	prepare the context and panic recovery
 
 	if setting.ReverseProxyLimit > 0 && len(setting.ReverseProxyTrustedProxies) > 0 {
 		handlers = append(handlers, ForwardedHeadersHandler(setting.ReverseProxyLimit, setting.ReverseProxyTrustedProxies))