Fix comment typos and formatting in str_split.h

Fixes a mismatched quote around `std::map` and adds missing whitespace after a comma in the container list.

This fixes tooltip formatting.

PiperOrigin-RevId: 1004142437

absl/strings/str_split.h

diff --git a/absl/strings/str_split.h b/absl/strings/str_split.h
index dc32af1..2d64394 100644
--- a/absl/strings/str_split.h
+++ b/absl/strings/str_split.h
@@ -452,7 +452,8 @@
 // behavior works for:
 //
 // 1) All standard STL containers including `std::vector`, `std::list`,
-//    `std::deque`, `std::set`,`std::multiset`, 'std::map`, and `std::multimap`.
+//    `std::deque`, `std::set`, `std::multiset`, `std::map`, and
+//    `std::multimap`.
 // 2) `std::pair` (which is not actually a container). See below.
 // 3) `std::array`, which is a container but has different behavior due to its
 //    fixed size. See below.