Add LAMMPSLexer for LAMMPS code-blocks in docs

doc/src/Commands_parse.rst

@@ -22,6 +22,10 @@ comment after a trailing "&" character will prevent the command from
 continuing on the next line.  Also note that for multi-line commands a
 single leading "#" will comment out the entire command.
 
+.. code-block:: LAMMPS
+
+   # this is a comment
+
 (3) The line is searched repeatedly for $ characters, which indicate
 variables that are replaced with a text string.  See an exception in
 (6).
@@ -47,7 +51,7 @@ to use numeric formulas in an input script without having to assign
 them to variable names.  For example, these 3 input script lines:
 
 
-.. parsed-literal::
+.. code-block:: LAMMPS
 
    variable X equal (xlo+xhi)/2+sqrt(v_area)
    region 1 block $X 2 INF INF EDGE EDGE
@@ -56,7 +60,7 @@ them to variable names.  For example, these 3 input script lines:
 can be replaced by
 
 
-.. parsed-literal::
+.. code-block:: LAMMPS
 
    region 1 block $((xlo+xhi)/2+sqrt(v_area)) 2 INF INF EDGE EDGE
 
@@ -72,7 +76,7 @@ specified a high-precision "%.20g" is used as the default.
 This can be useful for formatting print output to a desired precision:
 
 
-.. parsed-literal::
+.. code-block:: LAMMPS
 
    print "Final energy per atom: $(pe/atoms:%10.3f) eV/atom"
 
@@ -81,7 +85,7 @@ contain nested $ characters for other variables to substitute for.
 Thus you cannot do this:
 
 
-.. parsed-literal::
+.. code-block:: LAMMPS
 
    variable        a equal 2
    variable        b2 equal 4
@@ -113,7 +117,7 @@ can be enclosed in triple quotes, in which case "&" characters are not
 needed.  For example:
 
 
-.. parsed-literal::
+.. code-block:: LAMMPS
 
    print "Volume = $v"
    print 'Volume = $v'