Ported missing Additions and Updates section in Maps

Author: eed3si9n

overviews/collections/maps.md

@@ -29,6 +29,11 @@ The fundamental operations on maps are similar to those on sets. They are summar
 |`ms contains k`|Tests whether `ms` contains a mapping for key `k`.|
 |`ms isDefinedAt k`|Same as `contains`. |
 |**Additions and Updates:**||
+|`ms + (k -> v)`|The map containing all mappings of `ms` as well as the mapping `k -> v` from key `k` to value `v`.|
+|`ms + (k -> v, l -> w)`|The map containing all mappings of `ms` as well as the given key/value pairs.|
+|`ms ++ kvs`|The map containing all mappings of `ms` as well as all key/value pairs of `kvs`.|
+|`ms updated (k, v)`|Same as `ms + (k -> v)`.|
+|**Removals:**||
 |`ms - k`|The map containing all mappings of `ms` except for any mapping of key `k`.|
 |`ms - (k, 1, m)`|The map containing all mappings of `ms` except for any mapping with the given keys.|
 |`ms -- ks`|The map containing all mappings of `ms` except for any mapping with a key in `ks`.|