add reference to the fix_modify command overview in fix atc docs into all atc subcommand docs

doc/src/atc_control_localized_lambda.rst

@@ -0,0 +1,46 @@
+.. index:: fix_modify AtC control localized_lambda
+
+fix_modify AtC control localized_lambda command
+===============================================
+
+Syntax
+""""""
+
+.. parsed-literal::
+
+   fix_modify <AtC fixID> control localized_lambda <on|off>
+
+* AtC fixID = ID of :doc:`fix atc <fix_atc>` instance
+* control localized_lambda = name of the AtC sub-command
+* *on* or *off* = Toggles state of localization algorithm
+
+Examples
+""""""""
+
+.. code-block:: LAMMPS
+
+   fix_modify AtC control localized_lambda on
+
+Description
+"""""""""""
+
+Turns the localization algorithms *on* or *off* for control algorithms
+to restrict the influence of FE coupling or boundary conditions to a
+region near the boundary of the MD region.  Control algorithms will not
+affect atoms in elements not possessing faces on the boundary of the
+region.  Flux-based control is localized via row-sum lumping while
+quantity control is done by solving a truncated matrix equation.
+
+Restrictions
+""""""""""""
+
+None.
+
+Related AtC commands
+""""""""""""""""""""
+- :ref:`fix_modify AtC command overview <atc_fix_modify>`
+
+Default
+"""""""
+
+off