Docs: Clearly separate Operand-related paragraphs.

llvm-svn: 194977
diff --git a/llvm/docs/WritingAnLLVMBackend.rst b/llvm/docs/WritingAnLLVMBackend.rst
index 0d29210..5dd55d0 100644
--- a/llvm/docs/WritingAnLLVMBackend.rst
+++ b/llvm/docs/WritingAnLLVMBackend.rst
@@ -911,6 +911,9 @@
 fields.  This results in the ``XNORrr`` instruction binding ``$dst``, ``$b``,
 and ``$c`` operands to the ``rd``, ``rs1``, and ``rs2`` fields respectively.
 
+Instruction Operand Name Mapping
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 TableGen will also generate a function called getNamedOperandIdx() which
 can be used to look up an operand's index in a MachineInstr based on its
 TableGen name.  Setting the UseNamedOperandTable bit in an instruction's
@@ -952,6 +955,9 @@
     int16_t getNamedOperandIdx(uint16_t Opcode, uint16_t NamedIndex);
   } // End namespace XXX
 
+Instruction Scheduling
+----------------------
+
 Instruction itineraries can be queried using MCDesc::getSchedClass(). The
 value can be named by an enumemation in llvm::XXX::Sched namespace generated
 by TableGen in XXXGenInstrInfo.inc. The name of the schedule classes are