[dx] add gen docs to gitignore (#2704)

This PR ignores generated markdown files.

### Change Type

- [x] `internal` — Any other changes that don't affect the published
package[^2]

.gitignore

@@ -83,7 +83,7 @@ apps/examples/build.esbuild.json
 apps/examples/e2e/test-results
 apps/examples/playwright-report
 
-docs/gen
+apps/docs/content/gen
 
 .dev.vars
 .env.local