Simple spell checker
g++ -o spell_check main.cpp -std=c++20 -I ../lexertl17/include -I ../../boost_1_77_0
spell_check [pathname...] [(--word-regex|-w) <regex>] ((--dictionary|-d) <pathname to whitespace separated word list>)+
Note that if no pathnames are supplied, input is taken from stdin.
Google: dictionary word list text file for sample dictionaries.
If words in the dictionary are all lower case, then checking will
be case insensitive or case sensitive otherwise.