Fix typo and incorrect variable name in balance.c comment (#254)

* Add balance.c|h

* Improve do-single-output help

* Carbon and nitrogen balance checks

* Add event fluxes to track system inputs and outputs; add nppStorage pool to envi

* Add external writeEvent function, refactor original

* Add event for leaf on/off; split woodC into two pools; add balance checks

* Updates for balance checks and leaf on/off events

* Add ability to compare to base

* Remove tolerance from balance tracker

* Update col list for niwot

* Avoid negative zero

* Remove negative zeros

* Add test for balance check

* PR feedback

* Turn off microbes, as it is now broken

* Test updates after balance check updates

* Split leaf-on carbon creation into own flux

* Fix leafOn flux

* Updates for leafOn split

* Force skipping russell_4

* Update for new event fluxes

* Initial plan

* Fix typo and incorrect variable name in balance.c comment

Co-authored-by: dlebauer <464871+dlebauer@users.noreply.github.com>

* Remove unnecessary test files

---------

Co-authored-by: Mike Longfritz <Mike.Longfritz@gmail.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: dlebauer <464871+dlebauer@users.noreply.github.com>

Author: 3 people

src/sipnet/balance.c

@@ -18,8 +18,8 @@ void getMassTotals(double *carbon, double *nitrogen) {
   }
 
   if (ctx.nitrogenCycle) {
-    // Note: this is the one place where we ust plantWoodC by itself; it's the
-    // reason plantNSCWoodCDelta was created, so that we can ignore it here.
+    // Note: this is the one place where we use plantWoodC by itself; it's the
+    // reason plantWoodCStorageDelta was created, so that we can ignore it here.
     *nitrogen =
         envi.plantWoodC / params.woodCN + envi.plantLeafC / params.leafCN +
         envi.fineRootC / params.fineRootCN + envi.coarseRootC / params.woodCN +