Updated imports to /core

Author: D-K-P

docs/config/config-file.mdx

@@ -511,7 +511,7 @@ The `vercelSyncEnvVars` build extension syncs environment variables from your Ve
 
 ```ts
 import { defineConfig } from "@trigger.dev/sdk/v3";
-import { vercelSyncEnvVars } from "@trigger.dev/build/extensions/vercelSyncEnvVars";
+import { vercelSyncEnvVars } from "@trigger.dev/build/extensions/core";
 
 export default defineConfig({
   project: "<project ref>",

docs/guides/examples/vercel-sync-env-vars.mdx

@@ -23,7 +23,7 @@ This code syncs encrypted environment variables, filtering them based on the cur
 
 ```ts trigger.config.ts
 import { defineConfig } from "@trigger.dev/sdk/v3";
-import { vercelSyncEnvVars } from "@trigger.dev/build/extensions/vercelSyncEnvVars";
+import { vercelSyncEnvVars } from "@trigger.dev/build/extensions/core";
 
 export default defineConfig({
   project: "<project ref>",

docs/guides/frameworks/nextjs.mdx

@@ -256,7 +256,7 @@ If you want to automatically sync environment variables from your Vercel project
 
 ```ts trigger.config.ts
 import { defineConfig } from "@trigger.dev/sdk/v3";
-import { vercelSyncEnvVars } from "@trigger.dev/build/extensions/vercelSyncEnvVars";
+import { vercelSyncEnvVars } from "@trigger.dev/build/extensions/core";
 
 export default defineConfig({
   project: "<project ref>",