Document path use bias options in the manpage.

doc/tor.1.txt

@@ -1242,16 +1242,11 @@ The following options are useful only for clients (that is, if
 
 **PathBiasMultFactor** __NUM__ +
 
-**PathBiasScaleFactor** __NUM__ +
-
-**PathBiasUseCloseCounts** __NUM__::
+**PathBiasScaleFactor** __NUM__::
     These options override the default behavior of Tor's (**currently
     experimental**) path bias detection algorithm. To try to find broken or
     misbehaving guard nodes, Tor looks for nodes where more than a certain
-    fraction of circuits through that guard fail to get built. If
-    PathBiasUseCloseCounts is set to 1 (the default), usage-based accounting is
-    performed, and circuits that fail to carry streams are also counted as
-    failures. +
+    fraction of circuits through that guard fail to get built.
  +
     The PathBiasCircThreshold option controls how many circuits we need to build
     through a guard before we make these checks.  The PathBiasNoticeRate,
@@ -1270,6 +1265,28 @@ The following options are useful only for clients (that is, if
     If no defaults are available there, these options default to 150, .70,
     .50, .30, 0, 300, 1, and 2 respectively.
 
+**PathBiasUseThreshold** __NUM__ +
+
+**PathBiasNoticeUseRate** __NUM__ +
+
+**PathBiasExtremeUseRate** __NUM__ +
+
+**PathBiasScaleUseThreshold** __NUM__::
+    Similar to the above options, these options override the default behavior
+    of Tor's (**currently experimental**) path use bias detection algorithm.
+ +
+    Where as the path bias parameters govern thresholds for successfully
+    building circuits, these four path use bias parameters govern thresholds
+    only for circuit usage. Circuits which receive no stream usage
+    are not counted by this detection algorithm. A used circuit is considered
+    successful if it is capable of carrying streams or otherwise receiving
+    well-formed responses to RELAY cells.
+ +
+    By default, or if a negative value is provided for one of these options,
+    Tor uses reasonable defaults from the networkstatus consensus document.
+    If no defaults are available there, these options default to 20, .90,
+    .70, and 100, respectively.
+
 **ClientUseIPv6** **0**|**1**::
     If this option is set to 1, Tor might connect to entry nodes over
     IPv6. Note that clients configured with an IPv6 address in a