clang-tidy: use bool literals

Found with modernize-use-bool-literals

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/Lexer.cpp

@@ -910,7 +910,7 @@ bool Lexer::isPath (std::string& token, Lexer::Type& type)
   std::size_t marker = _cursor;
   int slashCount = 0;
 
-  while (1)
+  while (true)
   {
     if (_text[marker] == '/')
     {

src/recur2.cpp

@@ -291,7 +291,7 @@ static std::vector <Datetime> generateAllDueDates (const Task& templateTask)
   int recurrence_counter = 0;
   Datetime now;
 
-  while (1)
+  while (true)
   {
     Datetime nextDue = generateNextDueDate (due, recur, lastN);