Fix various typos

Found via codespell v1.17.0.dev0  
```
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,connexion,currenty,dof,doubleclick,dum,eiter,elemente,ende,feld,finde,findf,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/Mod/Part/AttachmentEditor/TaskAttachmentEditor.py

@@ -599,7 +599,7 @@ class AttachmentEditorTaskPanel(FrozenClass):
                                               .format(  mode=   self.attacher.getModeInfo(self.getCurrentMode())['UserFriendlyName']  )    )
                 if PlacementsFuzzyCompare(self.obj.Placement, new_plm) == False:
                     # assign only if placement changed. this avoids touching the object
-                    # when entering and extiting dialog without changing anything
+                    # when entering and exiting dialog without changing anything
                     self.obj.Placement = new_plm
         except Exception as err:
             self.form.message.setText(_translate('AttachmentEditor',"Error: {err}",None).format(err= str(err)))