[expr.await] Remove hyphen from "re-thrown" (#5062)

Author: jwakely

source/expressions.tex

@@ -4702,7 +4702,7 @@
 If the evaluation of \placeholder{await-suspend}
 exits via an exception, the exception is caught,
 the coroutine is resumed, and the exception is immediately
-re-thrown\iref{except.throw}. Otherwise, control flow returns
+rethrown\iref{except.throw}. Otherwise, control flow returns
 to the current coroutine caller or resumer\iref{dcl.fct.def.coroutine}
 without exiting any scopes\iref{stmt.jump}.