chore: add blas and extended keywords to @stdlib/blas/ext/base/ndarray/scusumors

Insert `blas` and `extended` after `math` in `package.json` keywords,
matching 75/87 (86%) of `blas/ext/base/ndarray` siblings and the
strided sibling `@stdlib/blas/ext/base/scusumors`, both of which already
list these keywords.

Author: claude

lib/node_modules/@stdlib/blas/ext/base/ndarray/scusumors/package.json

@@ -55,6 +55,8 @@
     "stats",
     "mathematics",
     "math",
+    "blas",
+    "extended",
     "cumulative",
     "accumulate",
     "sum",