Fix various typos in source code

This only touches code comments, class names, documentation,
enumeration names and tests.

src/libutil/hilite.cc

@@ -23,7 +23,7 @@ std::string hiliteMatches(
         auto m = *it;
         size_t start = m.position();
         out.append(s.substr(last_end, m.position() - last_end));
-        // Merge continous matches
+        // Merge continuous matches
         ssize_t end = start + m.length();
         while (++it != matches.end() && (*it).position() <= end) {
             auto n = *it;