add hover tooltip to rent expenses column

calc.js

@@ -49,6 +49,7 @@ function run_simulation(p) {
 
   // yearly accumulators (reset each year)
   let yr_interest = 0, yr_principal = 0, yr_upkeep = 0;
+  let yr_rent = 0, yr_renters_ins = 0;
 
   let breakeven_month = null;
 
@@ -81,6 +82,8 @@ function run_simulation(p) {
     // --- rent side ---
     const renters_ins_m = p.renters_ins / 12;
     const total_rent_m = monthly_rent + renters_ins_m;
+    yr_rent       += monthly_rent;
+    yr_renters_ins += renters_ins_m;
     cum_rent_cost += total_rent_m;
 
     // renter invests the difference if buying is more expensive
@@ -116,8 +119,11 @@ function run_simulation(p) {
         yr_interest:     Math.round(yr_interest),
         yr_principal:    Math.round(yr_principal),
         yr_upkeep:       Math.round(yr_upkeep),
+        yr_rent:         Math.round(yr_rent),
+        yr_renters_ins:  Math.round(yr_renters_ins),
       });
       yr_interest = 0; yr_principal = 0; yr_upkeep = 0;
+      yr_rent = 0; yr_renters_ins = 0;
     }
   }