Everywhere: Replace a bundle of dbg with dbgln.

These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.Everything:

The modifications in this commit were automatically made using the
following command:

    find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;

Libraries/LibRegex/RegexMatcher.cpp

@@ -310,7 +310,7 @@ Optional<bool> Matcher<Parser>::execute(const MatchInput& input, MatchState& sta
         auto* opcode = bytecode.get_opcode(state);
 
         if (!opcode) {
-            dbg() << "Wrong opcode... failed!";
+            dbgln("Wrong opcode... failed!");
             return {};
         }