docs: apply suggestions from cide review

Signed-off-by: Muhammad Haris <[email protected]>

Author: headlessNode

lib/node_modules/@stdlib/blas/ext/index-of/README.md

@@ -146,12 +146,12 @@ var array = require( '@stdlib/ndarray/array' );
 var x = array( [ 1.0, 2.0, 3.0, 4.0 ] );
 
 var idx = indexOf( x, 2.0, {
-    'dtype': 'generic'
+    'dtype': 'int32'
 });
 // returns <ndarray>
 
 var dt = dtype( idx );
-// returns 'generic'
+// returns 'int32'
 ```
 
 #### indexOf.assign( x, searchElement\[, fromIndex], out\[, options] )