Add options for controlling early termination criteria of CG/Newton linesearch.

Useful for performance tuning models.

PiperOrigin-RevId: 563175078
Change-Id: Id64a510d6080038ea8d5876dabbf0b2b311435bb

doc/XMLreference.rst

@@ -1972,6 +1972,18 @@ adjust it properly through the XML.
    improvement between two iterations. For CG and Newton, it is applied to the smaller of the cost improvement and the
    gradient norm. Set the tolerance to 0 to disable early termination.
 
+.. _option-ls_iterations:
+
+:at:`ls_iterations`: :at-val:`int, "50"`
+   Maximum number of linesearch iterations performed by CG/Newton constraint solvers. Ensures that at most
+   :ref:`iterations<option-iterations>` times :ref:`ls_iterations<option-ls_iterations>` linesearch iterations are
+   performed during each constraint solve.
+
+.. _option-ls_tolerance:
+
+:at:`ls_tolerance`: :at-val:`real, "0.01"`
+   Tolerance threshold used for early termination of the linesearch algorithm.
+
 .. _option-noslip_iterations:
 
 :at:`noslip_iterations`: :at-val:`int, "0"`