[NFC] Clear some clang-tidy warnings, small cleaup hctdb.py (#7724)

The majority of this change is just deleting and unnesting `else` cases
that follow `if () { return }` blocks

There are a couple removals of `{}` around one-line branches, and then I
updated `hctdb.py` to use the built in helper function for reserved ops
that were manually being reserved.

Author: V-FEXrt

docs/DXIL.rst

@@ -2340,18 +2340,18 @@ ID  Name                                                  Description
 223 TextureGatherRaw                                      Gather raw elements from 4 texels with no type conversions (SRV type is constrained)
 224 SampleCmpLevel                                        samples a texture and compares a single component against the specified comparison value
 225 TextureStoreSample                                    stores texel data at specified sample index
-226 Reserved0                                             Reserved
-227 Reserved1                                             Reserved
-228 Reserved2                                             Reserved
-229 Reserved3                                             Reserved
-230 Reserved4                                             Reserved
-231 Reserved5                                             Reserved
-232 Reserved6                                             Reserved
-233 Reserved7                                             Reserved
-234 Reserved8                                             Reserved
-235 Reserved9                                             Reserved
-236 Reserved10                                            Reserved
-237 Reserved11                                            Reserved
+226 Reserved0                                             reserved
+227 Reserved1                                             reserved
+228 Reserved2                                             reserved
+229 Reserved3                                             reserved
+230 Reserved4                                             reserved
+231 Reserved5                                             reserved
+232 Reserved6                                             reserved
+233 Reserved7                                             reserved
+234 Reserved8                                             reserved
+235 Reserved9                                             reserved
+236 Reserved10                                            reserved
+237 Reserved11                                            reserved
 238 AllocateNodeOutputRecords                             returns a handle for the output records
 239 GetNodeRecordPtr                                      retrieve node input/output record pointer in address space 6
 240 IncrementOutputCount                                  Select the next logical output count for an EmptyNodeOutput for the whole group or per thread.

include/dxc/DXIL/DxilConstants.h

@@ -496,18 +496,18 @@ inline bool IsFeedbackTexture(DXIL::ResourceKind ResourceKind) {
 // Enumeration for operations specified by DXIL
 enum class OpCode : unsigned {
   //
-  Reserved0 = 226,   // Reserved
-  Reserved1 = 227,   // Reserved
-  Reserved10 = 236,  // Reserved
-  Reserved11 = 237,  // Reserved
-  Reserved2 = 228,   // Reserved
-  Reserved3 = 229,   // Reserved
-  Reserved4 = 230,   // Reserved
-  Reserved5 = 231,   // Reserved
-  Reserved6 = 232,   // Reserved
-  Reserved7 = 233,   // Reserved
-  Reserved8 = 234,   // Reserved
-  Reserved9 = 235,   // Reserved
+  Reserved0 = 226,   // reserved
+  Reserved1 = 227,   // reserved
+  Reserved10 = 236,  // reserved
+  Reserved11 = 237,  // reserved
+  Reserved2 = 228,   // reserved
+  Reserved3 = 229,   // reserved
+  Reserved4 = 230,   // reserved
+  Reserved5 = 231,   // reserved
+  Reserved6 = 232,   // reserved
+  Reserved7 = 233,   // reserved
+  Reserved8 = 234,   // reserved
+  Reserved9 = 235,   // reserved
   ReservedA0 = 259,  // reserved
   ReservedA1 = 260,  // reserved
   ReservedA2 = 261,  // reserved