Add sway compiler (#7409)

Should be pretty self explanatory. I've added a corresponding PR to the
infra repo [here](https://github.com/compiler-explorer/infra/pull/1532)

Please let me know if there is anything I've done incorrectly here!
Thanks

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Co-authored-by: Matt Godbolt <matt@godbolt.org>

types/languages.interfaces.ts

@@ -90,6 +90,7 @@ export type LanguageKey =
     | 'solidity'
     | 'spice'
     | 'spirv'
+    | 'sway'
     | 'swift'
     | 'tablegen'
     | 'toit'