fix ref to beam chapter

track.asciidoc

@@ -13,10 +13,10 @@ endif::[]
 === Track Mode
 
 Before starting to track, a link:lines#chp.lines[`LINE`] and a 
-link:beam#chp.beam[`BEAM`] must be selected. The time step (`DT`) and the
-maximal steps to track (`MAXSTEPS`) or `ZSTOP` should be set. This
-command causes _OPAL_ to enter "tracking mode", in which it accepts
-only the track commands see <<tab_TRACK_Commands>>. In order to perform
+link:beam-command#chp.beam-command[`BEAM`] must be selected. The time
+step (`DT`) and the maximal steps to track (`MAXSTEPS`) or `ZSTOP` should be
+set. This command causes _OPAL_ to enter "tracking mode", in which it accepts
+only the track commands (see <<tab_TRACK_Commands>>). In order to perform
 several tracks, specify arrays of parameter in `DT`, `MAXSTEPS` and
 `ZSTOP`. This can be used to change the time step manually.
 
@@ -157,7 +157,7 @@ TRACK, LINE=name, BEAM=name, MAXSTEPS=value, STEPSPERTURN=value;
 Particles are tracked in parallel, i.e. the coordinates of all particles
 are transformed at each beam element as it is reached.
 
-_OPAL_ leaves *track mode* when it sees the command
+_OPAL_ leaves *track mode* when it sees the command 
 
 ----
 ENDTRACK;