Make internally-used method protected
Make internally-used method protected

thephpleague/commonmark,garethellis36/commonmark,kkiernan/commonmark,stof/commonmark,kkiernan/commonmark,fesor/commonmark,bcremer/commonmark,postalservice14/commonmark,postalservice14/commonmark,thephpleague/commonmark,fesor/commonmark,cebe/markdown-1,hason/commonmark,hason/commonmark,garethellis36/commonmark,colinodell/commonmark