add info about WACCA stats

docs/docs/user/stats/tachi.md

@@ -180,7 +180,7 @@ given score, which made the function painfully discrete.
 	point, and its flaws make it incredibly abusable.
 
 *****
-<!-- 
+<!--
 ### ktRating (DDR)
 
 - **Default for DDR SP and DDR DP**
@@ -229,7 +229,7 @@ As such, it only applies to a rather small subset of
 players and an even smaller subset of their scores.
 
 ***** -->
-<!-- 
+<!--
 ### KtRating (maimai)
 
 - **Default for maimai**
@@ -257,7 +257,9 @@ for maimai. Since maimai is a very accuracy oriented game,
 it punishes low-accuracy scores heavily.
 
 Scores below 90% are heavily nerfed. Timing is rewarded
-significantly. Clear type is ignored. -->
+significantly. Clear type is ignored.
+
+***** -->
 
 ### KtRating (MÚSECA)
 
@@ -287,6 +289,8 @@ algorithm (again!), with parameters tuned for MÚSECA.
 Scores below 900k are heavily nerfed. Timing is rewarded
 significantly. Clear type is ignored.
 
+*****
+
 ### Sieglinde (BMS)
 
 - **Default for BMS 7K and BMS 14K**
@@ -321,7 +325,7 @@ respectively.
 
 !!! info
 	For 7K, the currently supported tables are:
-	
+
 	- Insane1
 	- Insane2
 	- Normal1
@@ -332,6 +336,8 @@ respectively.
 
 	For 14K, no tables are currently supported.
 
+*****
+
 ### Rating (CHUNITHM)
 
 - **Default for CHUNITHM**
@@ -354,6 +360,8 @@ at the accuracy of the provided score.
 	implementation flaws of this algorithm for individual
 	scores.
 
+*****
+
 ### Skill (Gitadora)
 
 - **Default for GITADORA**
@@ -387,6 +395,28 @@ decently for what it is.
 
 *****
 
+### Rate (WACCA)
+
+- **Default for WACCA**
+
+Pros:
+
+- Built-in to the game.
+- Generally well-understood by players.
+- Uses the game's internal precise chart rating.
+
+Cons:
+
+- Significant favors good performance on charts released in
+  the most recent version of the game.
+- Uses wide cutoffs that don't reward AMs over SSS+.
+
+Although a better score statistic could be implemented, Rate
+is preferred since it is well-understood and can get the job
+done.
+
+*****
+
 ## Profile Statistics
 
 This section explains the statistics on a user's profile.
@@ -424,7 +454,7 @@ of making VF6 not a small decimal, and is generally how
 people talk about their volforce.
 
 *****
-<!-- 
+<!--
 ### DDR
 
 The below statistics apply to both SP and DP.
@@ -486,6 +516,29 @@ songs.
 
 *****
 
+### WACCA
+
+- Rate
+
+The sum of your best 15 Rate scores from the most recent
+version of the game, and your best 35 Rate scores from
+previous versions of the game.
+
+- Naive Rate **(Default)**
+
+The sum of your best 50 Rate scores.
+
+!!! info
+	Your Rate should pretty much match what you see
+	in-game. However, the in-game Rate advantages players on
+	the newest version of the game by weighting those charts
+	much more heavily, which is kind of dumb. NaiveRate
+	should eliminate this bias. In practice, for active
+	players on the newest version of the game, these values
+	are usually quite similar.
+
+*****
+
 ## Session Ratings
 
 This section explains the statistics on a session.
@@ -549,6 +602,8 @@ The average of the highest 10 KtRatings that session.
 
 The average of the highest 10 KtRatings that session.
 
+*****
+
 ### BMS
 
 The below information applies to both 7K and 14K.
@@ -557,12 +612,16 @@ The below information applies to both 7K and 14K.
 
 The average of the highest 10 Sieglinde ratings that session.
 
+*****
+
 ### CHUNITHM
 
 - Naive Rating **(Default)**
 
 The average of the highest 10 ratings that session.
 
+*****
+
 ### GITADORA
 
 - Skill **(Default)**
@@ -577,4 +636,12 @@ The average of the highest 10 skills achieved that session.
 	free to report it as an issue if you think it
 	should be added.
 
+*****
+
+### WACCA
+
+- Rate **(Default)**
+
+The average of the highest 10 Rates achieved that session.
+
 [^1]: Skill is obviously very loosely used here. If there was a consensus on what "skill" something was, we would already have a perfect rating algorithm.