Update doc/manual/source/release-notes-determinate/rl-3.6.3.md

Author: grahamc

doc/manual/source/release-notes-determinate/rl-3.6.3.md

@@ -13,6 +13,7 @@
 * Improve error messages that use the hypothetical future tense of "will" by @lucperkins in [DeterminateSystems/nix-src#92](https://github.com/DeterminateSystems/nix-src/pull/92)
 * Make the `nix repl` test more stable by @edolstra in [DeterminateSystems/nix-src#103](https://github.com/DeterminateSystems/nix-src/pull/103)
 * Run nixpkgsLibTests against lazy trees by @edolstra in [DeterminateSystems/nix-src#100](https://github.com/DeterminateSystems/nix-src/pull/100)
+* Run the Nix test suite against lazy trees by @edolstra in [DeterminateSystems/nix-src#105](https://github.com/DeterminateSystems/nix-src/pull/105)
 * Improve caching of inputs in dry-run mode by @edolstra in [DeterminateSystems/nix-src#98](https://github.com/DeterminateSystems/nix-src/pull/98)