Fix spelling errors

Most errors found with:

codespell -L cach,thst,odly,aslo,parm,parms,inpu,ges,prset,pevent,ptd,pring,valu,noo,noe,ned,inout,ro,siz,froms,nd,fo,singl,sart,multy,tthe,allong,ment,inate,nodel,tring,alse,ture,thi,wille,numer

Some more manually found (its -> it's)

c++20: Do not use apostrophe (e.g. can't) in unquoted #error message

modules/ca/src/client/bhe.cpp

@@ -192,7 +192,7 @@ bool bhe::updatePeriod (
         this->beaconAnomalyNotify ( guard );
 
         /*
-         * this is the 2nd beacon seen. We cant tell about
+         * this is the 2nd beacon seen. We can't tell about
          * the change in period at this point so we just
          * initialize the average period and return.
          */