Fix typos and whitespace

Found via `codespell -q 3 -L aci,ake,aline,alle,alledges,alocation,als,ang,anid,anormal,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,itsel,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,ro,rougly,seperator,serie,sinc,siz,strack,substraction,te,technic,thist,thru,tread,uint,unter,uptodate,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/Base/StackWalker.cpp,./build/doc/SourceDocu`

src/App/Document.h

@@ -361,7 +361,7 @@ public:
      * transactions, meaning that there are other transactions before the given
      * ID. The Gui component shall ask user if they want to undo multiple steps.
      * And if the user agrees, call undo(id) to unroll all transaction before
-     * and including the the one with the give ID. Same applies for redo.
+     * and including the one with the given ID. Same applies for redo.
      *
      * The new transaction ID describe here is fully backward compatible.
      * Calling the APIs with a default id=0 gives the original behavior.

src/App/FreeCADInit.py

@@ -24,7 +24,7 @@
 # FreeCAD init module
 #
 # Gathering all the information to start FreeCAD.
-# This is the second of of three init scripts.
+# This is the second of three init scripts.
 # The third one runs when the gui is up,
 
 # imports the one and only

src/App/LinkBaseExtensionPy.xml

@@ -35,7 +35,7 @@ depending on the actual extension object underlying this python
 object.
 
 If 'val' is omitted, i.e. calling configLinkProperty(key,...), then
-it is assumed the the actually property name is the same as 'key'
+it is assumed that the actual property name is the same as 'key'
         </UserDocu>
       </Documentation>
     </Methode>