Update directories meta data

Author: kgryte

lib/node_modules/@stdlib/stats/base/dists/truncated-normal/package.json

@@ -15,6 +15,7 @@
   ],
   "main": "./lib",
   "directories": {
+    "doc": "./docs",
     "example": "./examples",
     "lib": "./lib",
     "test": "./test"

lib/node_modules/@stdlib/strided/package.json

@@ -15,6 +15,7 @@
   ],
   "main": "./lib",
   "directories": {
+    "doc": "./docs",
     "example": "./examples",
     "lib": "./lib",
     "test": "./test"