docs: typo with the include_external_repositories example (#2582)

Close #2280

### Changes are visible to end-users: no

### Test plan

- Covered by existing test cases

Co-authored-by: Nadeesha Cabral <[email protected]>

Author: jbedard

docs/npm_package.md

@@ -282,7 +282,7 @@ def npm_package(
             `path/to/file` within the output directory.
 
             ```
-            npp_package(
+            npm_package(
                 name = "dir",
                 include_external_repositories = ["external_*"],
                 srcs = ["@external_repo//path/to:file"],