Fix typos and some trailing whitespace

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/Mod/Path/PathScripts/PathDressupRampEntry.py

@@ -501,7 +501,7 @@ class ObjectDressup:
         1. Start from the original startpoint of the plunge
         2. Calculate the distance on the path which is needed to implement the ramp
            and travel that distance while maintaining start depth
-        3. Start ramping while travelling the original path backwards until reaching the
+        3. Start ramping while traveling the original path backwards until reaching the
            original plunge end point
         4. Continue with the original path
         """
@@ -541,7 +541,7 @@ class ObjectDressup:
                     curPoint = newPoint
 
                 else:
-                    # we are travelling on start depth
+                    # we are traveling on start depth
                     newPoint = FreeCAD.Base.Vector(redge.valueAt(redge.LastParameter).x, redge.valueAt(redge.LastParameter).y, p0.z)
                     outedges.append(self.createRampEdge(redge, curPoint, newPoint))
                     curPoint = newPoint

src/Mod/Path/PathScripts/PathSurface.py

@@ -1262,8 +1262,8 @@ class ObjectSurface(PathOp.ObjectOp):
         pnt.y = RNG[0].y
         pnt.z = RNG[0].z + float(obj.DepthOffset.Value)
 
-        # Adjust feed rate based on radius/circumferance of cutter.
-        # Original feed rate based on travel at circumferance.
+        # Adjust feed rate based on radius/circumference of cutter.
+        # Original feed rate based on travel at circumference.
         if rN > 0:
             # if pnt.z > self.layerEndPnt.z:
             if pnt.z >= self.layerEndzMax:

src/Mod/Path/PathScripts/PathUtils.py

@@ -223,7 +223,7 @@ def horizontalFaceLoop(obj, face, faceList=None):
         outline = TechDraw.findShapeOutline(comp, 1, FreeCAD.Vector(0, 0, 1))
 
         # findShapeOutline always returns closed wires, by removing the
-        # trace-backs single edge spikes don't contriubte to the bound box
+        # trace-backs single edge spikes don't contribute to the bound box
         uniqueEdges = []
         for edge in outline.Edges:
             if any(PathGeom.edgesMatch(edge, e) for e in uniqueEdges):