fix typos, logic error, default in man page

doc/tor.1.txt

@@ -1096,9 +1096,9 @@ The following options are useful only for clients (that is, if
     "auto" (recommended) then it is on for all clients that do not set
     FetchUselessDescriptors. (Default: auto)
 
-**PathBiasCircTheshold** __NUM__ +
+**PathBiasCircThreshold** __NUM__ +
 
-**PathBiasNoticeRate** __NUM.__ +
+**PathBiasNoticeRate** __NUM__ +
 
 **PathBiasDisableRate** __NUM__ +
 
@@ -1112,7 +1112,7 @@ The following options are useful only for clients (that is, if
     PathBiasCircThreshold option controls how many circuits we need to build
     through a guard before we make these checks.  The PathBiasNoticeRate and
     PathBiasDisableRate options control what fraction of circuits must
-    succeed through a guard before we will warn about it or disable it,
+    succeed through a guard so we won't warn about it or disable it,
     respectively.  When we have seen more than PathBiasScaleThreshold
     circuits through a guard, we divide our observations by
     PathBiasScaleFactor, so that new observations don't get swamped by old
@@ -1121,7 +1121,7 @@ The following options are useful only for clients (that is, if
     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, .70,
-    .50, 200, and 4 respectively.
+    0.0, 200, and 4 respectively.
 
 
 SERVER OPTIONS