Rendering of mjGEOM_LINE respects size[0] (width argument of mjv_makeconnector), denominated in pixels.

- Before this change, line width was hardcoded to 3 pixels and the width argument of mjv_makeConnector was ignored.
- After this change, the width argument is respected and interpreted in units of pixel. The non-standard width unit is ok since lines can only be drawn programmatically.

PiperOrigin-RevId: 516529265
Change-Id: I27bffabba69cde415d2ada67263a887c9240efbf

introspect/functions.py

@@ -3630,7 +3630,7 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
                  type=ValueType(name='mjtNum'),
              ),
          ),
-         doc='Set (type, size, pos, mat) for connector-type geom between given points. Assume that mjv_initGeom was already called to set all other properties.',  # pylint: disable=line-too-long
+         doc='Set (type, size, pos, mat) for connector-type geom between given points. Assume that mjv_initGeom was already called to set all other properties. Width of mjGEOM_LINE is denominated in pixels.',  # pylint: disable=line-too-long
      )),
     ('mjv_defaultScene',
      FunctionDecl(