docs: re-add horizontal rule

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/stats/base/sstdev/README.md

@@ -330,6 +330,8 @@ int main( void ) {
 
 <section class="references">
 
+* * *
+
 ## References
 
 -   Neely, Peter M. 1966. "Comparison of Several Algorithms for Computation of Means, Standard Deviations and Correlation Coefficients." _Communications of the ACM_ 9 (7). Association for Computing Machinery: 496–99. doi:[10.1145/365719.365958][@neely:1966a].