tiny C support; cosmetic improvements for the docs

doc/keywords.txt

@@ -0,0 +1,19 @@
+addr and as asm atomic
+bind block break
+case cast const continue converter
+discard distinct div
+elif else end enum except
+finally for from generic
+if implies import in include is isnot iterator
+lambda let
+macro method mod
+nil not notin
+object of or out
+proc ptr
+raise ref return
+shl shr
+template try tuple type
+var
+when while with without
+xor
+yield