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/Mod/Show/Containers.py

@@ -182,7 +182,7 @@ def _getMetacontainerChildren(container, isrightcontainer_func):
 
 def isAContainer(obj, links_too = False):
     '''isAContainer(obj, links_too): returns True if obj is an object container, such as 
-    Group, Part, Body. The important characterisic of an object being a 
+    Group, Part, Body. The important characteristic of an object being a 
     container is that it can be activated to receive new objects. Documents 
     are considered containers, too.
     If links_too, App::Link objects are considered containers, too. Then, container tree