Add LiteralFloat to operand_kinds (KhronosGroup#380)

LiteralFloat was introduced with FPMaxErrorDecorationINTEL, but no entry in operand_kinds corresponds to it

Author: rAzoR8

include/spirv/unified1/spirv.core.grammar.json

@@ -16550,6 +16550,11 @@
       "kind" : "LiteralString",
       "doc" : "A null-terminated stream of characters consuming an integral number of words"
     },
+    {
+      "category" : "Literal",
+      "kind" : "LiteralFloat",
+      "doc" : "A float consuming one word"
+    },
     {
       "category" : "Literal",
       "kind" : "LiteralContextDependentNumber",