Fix various (doxy) typos and whitespace issues

Found via `codespell -q 3 -L aci,ake,aline,alle,alledges,alocation,als,ang,anid,ba,beginn,behaviour,bloaded,byteorder,calculater,cancelled,cancelling,cas,cascade,centimetre,childs,colour,colours,commen,currenty,dof,doubleclick,dum,eiter,elemente,feld,freez,hist,iff,indicies,initialisation,initialise,initialised,initialises,initialisiert,ist,kilometre,lod,mantatory,methode,metres,millimetre,modell,nd,noe,normale,normaly,nto,numer,oder,orgin,orginx,orginy,ot,pard,pres,programm,que,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`

src/App/Document.cpp

@@ -193,7 +193,7 @@ struct DocumentP
         static std::random_device _RD;
         static std::mt19937 _RGEN(_RD());
         static std::uniform_int_distribution<> _RDIST(0,5000);
-        // Set some random offset to reduce likelihood of ID collison when
+        // Set some random offset to reduce likelihood of ID collision when
         // copying shape from other document. It is probably better to randomize
         // on each object ID.
         lastObjectId = _RDIST(_RGEN); 
@@ -4129,7 +4129,7 @@ DocumentObject* Document::moveObject(DocumentObject* obj, bool recursive)
     if(objs.empty()) 
         return 0;
     // Some object may delete its children if deleted, so we collect the IDs
-    // or all depdending objects for safety reason.
+    // or all depending objects for safety reason.
     std::vector<int> ids;
     ids.reserve(deps.size());
     for(auto o : deps)