* std/lib: simplify String.{,r}index_of and improve speed for the index_of one
Signed-off-by: Pierre Curto <pierre.curto@gmail.com>
* lib/std/collections: add EnumMap.get_ref
Signed-off-by: Pierre Curto <pierre.curto@gmail.com>
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Signed-off-by: Pierre Curto <pierre.curto@gmail.com>