Don't break multi-line strings

[zultron]

AlwaysBreakBeforeMultilineStrings: false will make the following
change, causing howls. Setting it true didn't make any difference
on other parts of code (it won't try to recombine multi-line strings).

-const std::unordered_map<uint, std::string> BLAH_BLAH_MAP(
-    { { ITEM_UNO, "Lorem ipsum dolor sit amet, consectetur adipiscing" },
-      { ITEM_DOS_SUPER_DUPER_YUCK,
-        "Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium "
-        "doloremque" },
- [...]
+const std::unordered_map<uint, std::string> BLAH_BLAH_MAP({ { ITEM_UNO, "Lorem ipsum dolor sit amet, consectetur "
+                                                                         "adipiscing" },
+                                                             { ITEM_DOS_SUPER_DUPER_YUCK, "Sed ut perspiciatis "
+                                                                                          "unde omnis iste natus "
+                                                                                          "error sit voluptatem "
+                                                                                          "accusantium" },
+ [...]

[davetcoleman]

@rhaschke do you think this change makes sense for ROS 1 clang format?

[rhaschke]

The key issue here is that the false setting results in splitting a long string into many short lines if (and only if) the string starts at a high column number. On the other hand, always splitting will result in undesired formatting if the long string starts in a low column:

true:                                  false:
aaaa =                         vs.     aaaa = "bbbb"
    "bbbb"                                    "cccc";
    "cccc";

So, both approaches have their pros and cons. I don't really care.