Update RELEASE-NOTES.md

Author: awray3

Diff for: RELEASE-NOTES.md

@@ -20,7 +20,7 @@ It also brings some dreadfully awaited fixes, so be sure to go through the chang
 - `OrderedProbit` distribution added (see [#4232](https://github.com/pymc-devs/pymc3/pull/4232)).
 - `plot_posterior_predictive_glm` now works with `arviz.InferenceData` as well (see [#4234](https://github.com/pymc-devs/pymc3/pull/4234))
 - Add `logcdf` method to all univariate discrete distributions (see [#4387](https://github.com/pymc-devs/pymc3/pull/4387)).
-- Add `random` method to `MvGaussianRandomWalk` (see [#4388](https://github.com/pymc-devs/pymc3/issues/4337))
+- Add `random` method to `MvGaussianRandomWalk` (see [#4388](https://github.com/pymc-devs/pymc3/pull/4388))
 
 ### Maintenance
 - Fixed bug whereby partial traces returns after keyboard interrupt during parallel sampling had fewer draws than would've been available [#4318](https://github.com/pymc-devs/pymc3/pull/4318)