Update documentation with new selector keys.

src/ifcopenshell-python/docs/ifcopenshell-python/hello_world.rst

@@ -45,7 +45,7 @@ By selecting elements by their **IFC Class**, and reading their attributes, you
 can navigate from one element to another. The relationships between elements are
 called **IFC Concepts** and create meaning in our industry. For example, if a
 **IfcWall** element has an attribute that references an **IfcBuildingStorey**
-element in a particular way, it might mean that the wall is located in the
+element in a particular way, it will mean that the wall is located in the
 ground floor of the building.
 
 .. image:: images/ifc-concepts.svg

src/ifcopenshell-python/docs/ifcopenshell-python/selector_syntax.rst

@@ -184,6 +184,12 @@ Valid keys are:
     "``material`` or ``mat``", "Gets the assigned material, which may be a material set."
     "``item`` or ``i``", "If the previous key returns a material set, gets the relevant material set items"
     "``materials`` or ``mats``", "Gets a list of IfcMaterials assigned directly or indirectly (such as via a material set) to the element"
+    "``x``", "Gets the X coordinate of the element's placement"
+    "``y``", "Gets the Y coordinate of the element's placement"
+    "``z``", "Gets the Z coordinate of the element's placement"
+    "``easting``", "Gets the map easting of the element's placement"
+    "``northing``", "Gets the map northing of the element's placement"
+    "``elevation``", "Gets the map elevation of the element's placement"
     "``count``", "If the previous key returns multiple things, count that list. Otherwise, return 1."
     "``{{number}}``", "If the previous key returns multiple things, fetch the ``{{number}}`` index (e.g. 0, 1, 2, 3, etc) item in that list."