[basic.scope.param] Add missing \grammarterm for requires-expression (#6759)

Author: AlisdairM

source/basic.tex

@@ -1351,7 +1351,7 @@
 in the \grammarterm{lambda-expression}.
 \item
 If $P$ is associated with a \grammarterm{requirement-parameter-list},
-its scope extends to the end of the \grammarterm{requirement-body} of the requires-expression.
+its scope extends to the end of the \grammarterm{requirement-body} of the \grammarterm{requires-expression}.
 \item
 If $P$ is associated with a \grammarterm{deduction-guide},
 its scope extends to the end of the \grammarterm{deduction-guide}.