Fix more typos + whitespace fix and added 'TODO'

Found via `codespell -q 3 -L aci,ake,aline,alle,alledges,alocation,als,ang,anid,apoints,ba,beginn,behaviour,bloaded,bottome,byteorder,calculater,cancelled,cancelling,cas,cascade,centimetre,childrens,childs,colour,colours,commen,connexion,currenty,dof,doubleclick,dum,eiter,elemente,ende,feld,finde,findf,freez,hist,iff,indicies,initialisation,initialise,initialised,initialises,initialisiert,inout,ist,kilometre,lod,mantatory,methode,metres,millimetre,modell,nd,noe,normale,normaly,nto,numer,oce,oder,ontop,orgin,orginx,orginy,ot,pard,parm,parms,pres,programm,que,rady,recurrance,rougly,seperator,serie,sinc,strack,substraction,te,thist,thru,tread,uint,unter,vertexes,wallthickness,whitespaces -S ./.git,*.po,*.ts,./ChangeLog.txt,./src/3rdParty,./src/Mod/Assembly/App/opendcm,./src/CXX,./src/zipios++,./src/Base/swig*,./src/Mod/Robot/App/kdl_cp,./src/Mod/Import/App/SCL,./src/WindowsInstaller,./src/Doc/FreeCAD.uml,./build/doc/SourceDocu`

src/Mod/Arch/exportIFCStructuralTools.py

@@ -251,8 +251,8 @@ def createStructuralMember(ifcfile, ifcbin, obj):
         topologyRep = ifcfile.createIfcTopologyRepresentation(structContext, "Analysis", "Face", (face,))
         prodDefShape = ifcfile.createIfcProductDefinitionShape(None, None, (topologyRep,))
         # sets surface thickness
-        # ATM limitations
-        # - for verical slabs (walls) or inclined slabs (ramps) the thickness is taken from the Height property
+        # TODO: ATM limitations
+        # - for vertical slabs (walls) or inclined slabs (ramps) the thickness is taken from the Height property
         thickness = float(obj.Height)*scaling
         # creates structural member
         structuralMember = ifcfile.createIfcStructuralSurfaceMember(