[llvm] [RISCV] Rename some DecoderNamespaces and cleanup debug messages. NFC (PR #131409)

[Alex Bradbury via llvm-commits]

================
@@ -728,16 +726,16 @@ DecodeStatus RISCVDisassembler::getInstruction32(MCInst &MI, uint64_t &Size,
 
 static constexpr DecoderListEntry DecoderList16[]{
     // Vendor Extensions
-    {DecoderTableXqci16, XqciFeatureGroup, "Qualcomm uC 16bit"},
+    {DecoderTableXqci16, XqciFeatureGroup, "Qualcomm uC 16-bit"},
     {DecoderTableXqccmp16,
      {RISCV::FeatureVendorXqccmp},
      "Xqccmp (Qualcomm 16-bit Push/Pop & Double Move Instructions)"},
     {DecoderTableXwchc16, {RISCV::FeatureVendorXwchc}, "WCH QingKe XW"},
     // Standard Extensions
     // DecoderTableZicfiss16 must be checked before DecoderTable16.
-    {DecoderTableZicfiss16, {}, "RVZicfiss (Shadow Stack)"},
-    {DecoderTable16, {}, "RISCV_C (16-bit Instruction)"},
-    {DecoderTableRISCV32Only_16, {}, "RISCV32Only_16 (16-bit Instruction)"},
+    {DecoderTableZicfiss16, {}, "Zicfiss (Shadow Stack 16-bit)"},
+    {DecoderTable16, {}, "standard 16-bit Instructions"},
----------------
asb wrote:

To be consistent with the 32-bit instruction tables we probably want "instructions" rather than "Instructions" (in the line below too).

https://github.com/llvm/llvm-project/pull/131409