Little maintenance update

* Little documentation fixes
  * Added virtual destructor to emit helpers to silence warnings of
    some compilers (it's totally useless change though as it changes
    nothing in reality - emit helpers are allocated mostly on stack)

src/asmjit/arm/a64emithelper_p.h

@@ -24,6 +24,8 @@ public:
   ASMJIT_INLINE_NODEBUG explicit EmitHelper(BaseEmitter* emitter = nullptr) noexcept
     : BaseEmitHelper(emitter) {}
 
+  ASMJIT_INLINE_NODEBUG virtual ~EmitHelper() noexcept = default;
+
   Error emitRegMove(
     const Operand_& dst_,
     const Operand_& src_, TypeId typeId, const char* comment = nullptr) override;

src/asmjit/core.h

@@ -742,8 +742,9 @@ namespace asmjit {
 //!   JitAllocator::Span span;
 //!   Error err = allocator.alloc(span, estimatedSize);
 //!
-//!   if (err != kErrorOk) // <- NOTE: This must be checked, always!
+//!   if (err != kErrorOk) { // <- NOTE: This must be checked, always!
 //!     return 0;
+//!   }
 //!
 //!   // Now relocate the code to the address provided by the memory allocator.
 //!   // Please note that this DOESN'T COPY anything to it. This function will
@@ -780,15 +781,16 @@ namespace asmjit {
 //!   int out[4];
 //!
 //!   // This code uses AsmJit's ptr_as_func<> to cast between void* and SumIntsFunc.
-//!   ptr_as_func<SumIntsFunc>(p)(out, inA, inB);
+//!   SumIntsFunc fn = ptr_as_func<SumIntsFunc>(span.rx());
+//!   fn(out, inA, inB);
 //!
 //!   // Prints {5 8 4 9}
 //!   printf("{%d %d %d %d}\n", out[0], out[1], out[2], out[3]);
 //!
-//!   // Release 'p' is it's no longer needed. It will be destroyed with 'vm'
+//!   // Release `fn` is it's no longer needed. It will be destroyed with 'vm'
 //!   // instance anyway, but it's a good practice to release it explicitly
 //!   // when you know that the function will not be needed anymore.
-//!   allocator.release(p);
+//!   allocator.release(fn);
 //!
 //!   return 0;
 //! }

src/asmjit/core/emithelper_p.h

@@ -24,6 +24,8 @@ public:
   ASMJIT_INLINE_NODEBUG explicit BaseEmitHelper(BaseEmitter* emitter = nullptr) noexcept
     : _emitter(emitter) {}
 
+  ASMJIT_INLINE_NODEBUG virtual ~BaseEmitHelper() noexcept = default;
+
   ASMJIT_INLINE_NODEBUG BaseEmitter* emitter() const noexcept { return _emitter; }
   ASMJIT_INLINE_NODEBUG void setEmitter(BaseEmitter* emitter) noexcept { _emitter = emitter; }
 

src/asmjit/x86/x86emithelper_p.h

@@ -34,6 +34,8 @@ public:
       _avxEnabled(avxEnabled || avx512Enabled),
       _avx512Enabled(avx512Enabled) {}
 
+  ASMJIT_INLINE_NODEBUG virtual ~EmitHelper() noexcept = default;
+
   Error emitRegMove(
     const Operand_& dst_,
     const Operand_& src_, TypeId typeId, const char* comment = nullptr) override;