genemichaels: add comment about cargoTestFlags

Adds a rationale about why cargoTestFlags is not used.

pkgs/by-name/ge/genemichaels/package.nix

@@ -18,6 +18,11 @@ rustPlatform.buildRustPackage rec {
   cargoHash = "sha256-FjggpBTzxj9AOJjUq5PmbuE/ImmTMpxN0se9uxRy4KQ=";
 
   cargoBuildFlags = [ "--package ${pname}" ];
+  # cargoTestFlags is not used because genemichaels is tightly coupled to the
+  # other crates in the workspace and by not setting it, we run all the tests.
+  # If a dependency crate is failing its tests, we want to know about it. For
+  # example, between versions 0.5.8 and 0.5.12, there was a failing test in one
+  # of the other workspace members that genemichaels depends on.
 
   meta = {
     description = "Even formats macros";