fix release notes

Author: ellishg

lld/docs/ReleaseNotes.rst

@@ -46,7 +46,7 @@ MachO Improvements
 
 * ``--separate-cstring-literal-sections`` emits cstring literal sections into sections defined by their section name.
   (`#158720 <https://github.com/llvm/llvm-project/pull/158720>`_)
-* cstrings sections are now tail merged.
+* ``--tail-merge-strings`` enables tail merging of cstring literals.
   (`#161262 <https://github.com/llvm/llvm-project/pull/161262>`_)
 
 WebAssembly Improvements