docs(web/blog): use local.di (not top-level var) in from-wirebox-to-wheelsdi services.cfm example

The `config/services.cfm` snippet used a top-level `var di = injector();`. A bare
top-level `var` statement compile-errors on Adobe CF (#3063) — `config/services.cfm`
is an included template, not a function body, so `var` isn't valid there on Adobe.
Lucee/BoxLang tolerate it, but the example as shipped breaks for Adobe readers who
copy it. Switch to the cross-engine-safe `local.di` form (matching the DI guide and
CLAUDE.md), and update the chained references to `local.di.*`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: Peter Amiri <petera@pai.com>

Author: Peter Amiri

web/content/blog/posts/from-wirebox-to-wheelsdi.md

@@ -46,10 +46,10 @@ PRs [#1883](https://github.com/wheels-dev/wheels/pull/1883) and [#1888](https://
 
 ```cfm
 // config/services.cfm — in-house DI, familiar surface
-var di = injector();
-di.map("emailService").to("app.lib.EmailService").asSingleton();
-di.map("currentUser").to("app.lib.CurrentUserResolver").asRequestScoped();
-di.bind("INotifier").to("app.lib.SlackNotifier").asSingleton();
+local.di = injector();
+local.di.map("emailService").to("app.lib.EmailService").asSingleton();
+local.di.map("currentUser").to("app.lib.CurrentUserResolver").asRequestScoped();
+local.di.bind("INotifier").to("app.lib.SlackNotifier").asSingleton();
 ```
 
 Scopes are explicit. Transient is the default — a fresh instance per call. Singleton lives for the application lifetime. Request-scoped lives for the duration of one HTTP request, cached on `request.$wheelsDICache`. Auto-wiring of `init()` arguments matches registered names when no explicit `initArguments` are passed, which is the common case and the reason most service definitions fit on one line.