update compiler.texi

update compiler.texi

* doc/ref/compiler.texi (Compiler Tower): Update for removal of version
  from <language>, and add joiner and make-default-environment fields.
  Update examples.
  (The Scheme Compiler): Update for `macroexpand' instead of
  `sc-expand', and that the environment must be a module.
  (Tree-IL): Update for new Tree-IL, and change from "vars" to
  "gensyms".
  (GLIL): Update for new GLIL, including preludes and prompts.
  (Assembly): Update for current output (which seems quite verbose).
  (Bytecode and Objcode): Update for current output, and some procedure
  name changes.