[basic.contract.eval] Remove stray closing parenthesis (#7868)

Author: Andreas-Krug

source/basic.tex

@@ -7586,7 +7586,7 @@
 
 \begin{note}
 If a contract-violation handler
-invoked from an \grammarterm{assertion-statement}\iref{stmt.contract.assert})
+invoked from an \grammarterm{assertion-statement}\iref{stmt.contract.assert}
 exits via an exception,
 the search for a handler
 continues from the execution of that statement.