- Fixed some semantics issues to make data structure names more akin to their mathematical equivalents

- multiset.h TODO: test
 - Fixed some double underscores that I missed

planning/CONTAINERS.md

@@ -36,15 +36,16 @@ Library and Template Library.
 | bitset                               |      ❌      |   ❌    |
 | array                                |      ✔      |   ✔    |
 | dynarray (`std::vector`)             |      ⭕      |   ⭕    |
+| deque                                |      ❌      |   ❌    |
 | list                                 |      ✔      |   ✔    |
 | set (`std::unordered_set`)           |      ✔      |   ✔    |
-| ordered_set (`std::set`)             |      ❌      |   ❌    |
+| sequence (`std::set`)                |      ❌      |   ❌    |
 | map (`std::unordered_map`)           |      ✔      |   ✔    |
-| ordered_map (`std::map`)             |      ❌      |   ❌    |
+| map_sequence (`std::map`)            |      ❌      |   ❌    |
 | multiset (`std::unordered_multiset`) |      ❌      |   ❌    |
-| ordered_multiset (`std::multiset`)   |      ❌      |   ❌    |
+| multisequence (`std::multiset`)      |      ❌      |   ❌    |
 | multimap (`std::unordered_multimap`) |      ❌      |   ❌    |
-| ordered_multimap (`std::multimap`)   |      ❌      |   ❌    |
+| multimap_sequence (`std::multimap`)  |      ❌      |   ❌    |
 
 
 ### fennec