Fix parameter name

Author: kgryte

lib/node_modules/@stdlib/ndarray/base/char2dtype/README.md

@@ -40,7 +40,7 @@ limitations under the License.
 var char2dtype = require( '@stdlib/ndarray/base/char2dtype' );
 ```
 
-#### char2dtype( \[dtype] )
+#### char2dtype( \[ch] )
 
 Returns the [data type][@stdlib/ndarray/dtypes] string associated with a provided [single letter character abbreviation][@stdlib/ndarray/base/dtype-char].