[m-rev.] for review: list more new options in NEWS file

[Julien Fischer]

For review by Zoltan.

This adds all the new options since 20.06 that I could find based
on a diff of the 20.06 and ROTD usage messages.  There are two others.

1) --warn-potentially-ambiguous-pragma

We probably need to say something more generally about the changes
to pragma syntax.  (The new option can be mentioned alongside that.)

2) --output-stdlib-module

This is primarily for us and doesn't need to be documented.

-----------------------------------


List more new options in NEWS file.

NEWS:
     As above.

Julien.

diff --git a/NEWS b/NEWS
index 7c39eaf..76baf90 100644
--- a/NEWS
+++ b/NEWS
@@ -618,6 +618,19 @@ Changes to the Mercury compiler
  * The new option `--output-stdlib-grades` outputs the grades in which
    the Mercury standard library is available with this compiler.

+* By default, the compiler now warns if a program contains a module whose
+  name shadows that of Mercury standard library module. The warning can
+  be disabled using the new option `--no-warn-stdlib-shadowing`.
+
+* The new options `--output-java-class-dir` and `--output-java-class-directory`
+  are now supported as synonyms for `--output-class-dir`.
+
+* The new option `--halt-at-warn-make-interface` causes the compiler to
+  treat all warnings as if they were errors when generating interface files.
+
+* The new option `--halt-at-warn-make-opt` causes the compiler to
+  treat all warnings as if they were errors when generating optimization files.
+
  Portability improvements
  ------------------------