* Adding CXX 20 to CI
* side-stepping new CXX 20 guard.
* Going another way
* Saving.
* Explicit.
* Saving...
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Co-authored-by: Daniel Lemire <dlemire@lemire.me>
Closes#1894
Reject low surrogates outside of the range U+DC00—U+DFFF
Related to https://unicodebook.readthedocs.io/unicode_encodings.html#utf-16-surrogate-pairs
A surrogate pair should consist of a high surrogate and low surrogate.
They're used to represent 0x010000-0x10FFFF in the JSON spec because
the JavaScript specification originally only supported `\uXXXX`.
Previously, simdjson would accept some combinations of valid high
surrogates and invalid low surrogates due to a bug in the check.
(e.g. `\uD888\u1234` was accepted)
U+D800—U+DBFF (1,024 code points): high surrogates
U+DC00—U+DFFF (1,024 code points): low surrogates