[RISCV] Attempt to fix the link to the XAndesPerf specification. NFC

[topperc]

We need to use 2 underscores after the URL like the other specification links.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

Author: Craig Topper (topperc)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/138804.diff

1 Files Affected:

• (modified) llvm/docs/RISCVUsage.rst (+1-1)

diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
index d0689b779f551..4b98f58304f13 100644
--- a/llvm/docs/RISCVUsage.rst
+++ b/llvm/docs/RISCVUsage.rst
@@ -506,7 +506,7 @@ The current vendor extensions supported are:
   LLVM implements `version 0.1 of the Rivos Vector Register Zips extension specification <https://github.com/rivosinc/rivos-custom-extensions>`__.
 
 ``XAndesPerf``
-  LLVM implements `version 5.0.0 of the Andes Performance Extension specification <https://github.com/andestech/andes-v5-isa/releases/download/ast-v5_4_0-release/AndeStar_V5_ISA_Spec_UM165-v1.5.08-20250317.pdf>` by Andes Technology. All instructions are prefixed with `nds.` as described in the specification.
+  LLVM implements `version 5.0.0 of the Andes Performance Extension specification <https://github.com/andestech/andes-v5-isa/releases/download/ast-v5_4_0-release/AndeStar_V5_ISA_Spec_UM165-v1.5.08-20250317.pdf>`__ by Andes Technology. All instructions are prefixed with `nds.` as described in the specification.
 
 Experimental C Intrinsics
 =========================

[tclin914]

LGTM