Update llvm/docs/ReleaseNotes.rst.

Author: Yeting Kuo

llvm/docs/ReleaseNotes.rst

@@ -204,6 +204,8 @@ Changes to the RISC-V Backend
 * The WCH / Nanjing Qinheng Microelectronics QingKe "XW" compressed opcodes are
   supported under the name "Xwchc".
 * ``-mcpu=native`` now detects available features with hwprobe (RISC-V Hardware Probing Interface) on Linux 6.4 or later.
+=======
+* The version of Zicfilp/Zicfiss is updated to 1.0.
 
 Changes to the WebAssembly Backend
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