Add disclaimer to workload tooltip (#4131)

ftl/core/deck-config.ftl

@@ -425,6 +425,8 @@ deck-config-desired-retention-tooltip =
     less frequently, and you will forget more of them. Be conservative when adjusting this - higher
     values will greatly increase your workload, and lower values can be demoralizing when you forget
     a lot of material.
+deck-config-desired-retention-tooltip2 = 
+    The workload values provided by the tooltip are a rough approximation. For a greater level of accuracy, use the simulator.
 deck-config-historical-retention-tooltip =
     When some of your review history is missing, FSRS needs to fill in the gaps. By default, it will
     assume that when you did those old reviews, you remembered 90% of the material. If your old retention

ts/routes/deck-options/FsrsOptionsOuter.svelte

@@ -38,7 +38,10 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         },
         desiredRetention: {
             title: tr.deckConfigDesiredRetention(),
-            help: tr.deckConfigDesiredRetentionTooltip(),
+            help:
+                tr.deckConfigDesiredRetentionTooltip() +
+                "\n\n" +
+                tr.deckConfigDesiredRetentionTooltip2(),
             sched: HelpItemScheduler.FSRS,
         },
         modelParams: {