refactor: Fix spelling issues in all variables/functions (#6184)

This change fixes many typos in comments, variables, and public functions. There is no functionality change.

src/test/app/MultiSign_test.cpp

@@ -708,7 +708,7 @@ public:
     void
     testHeterogeneousSigners(FeatureBitset features)
     {
-        testcase("Heterogenious Signers");
+        testcase("Heterogenous Signers");
 
         using namespace jtx;
         Env env{*this, features};