add description for adjust_priority

src/wallet/wallet2.cpp

@@ -8632,6 +8632,11 @@ uint64_t wallet2::adjust_mixin(uint64_t mixin)
   return mixin;
 }
 //----------------------------------------------------------------------------------------------------
+// `adjust_priority` can be described as follows:
+// If the given priority is the default priority and `auto_low_priority` has been set, return one of the following (in order of preference):
+// (1) Priority 1 aka "unimportant" - When a transaction confirmation is unlikely to be delayed.
+// (2) Priority 2 aka "normal" - When the transaction is likely to benefit from a higher priority.
+// In all other cases, return the original priority unchanged.
 uint32_t wallet2::adjust_priority(uint32_t priority)
 {
   if (priority == 0 && m_default_priority == 0 && auto_low_priority())