[m-rev.] for post-commit review: further work on samples directory README

[Julien Fischer]

Further work on samples directory README.

samples/README.md:
     Make the top-level heading a level 1 heading.

     Add eliza.m and beer.m to the list of sample programs.

     Fix spelling.

Julien.

diff --git a/samples/README.md b/samples/README.md
index 811c381..08941fc 100644
--- a/samples/README.md
+++ b/samples/README.md
@@ -1,5 +1,5 @@
  Mercury Sample Programs
------------------------
+=======================

  This directory contains some example Mercury programs.

@@ -31,6 +31,12 @@ This directory contains some example Mercury programs.
    to however many digits you choose. It illustrates one way to achieve lazy
    evaluation in Mercury.

+* [eliza.m](eliza.m) -- An implementation of the famous computer
+  psychotherapist.
+
+* [beer.m](beer.m) -- A small program that prints the lyrics of the song
+  "99 Bottle of Beer".
+
  * [Mmakefile](Mmakefile) -- The file used by `mmake`, the Mercury Make program,
    to build the programs in this directory.

@@ -43,7 +49,7 @@ nondeterminism, showing how a Mercury program can compute

  for a query which has more than one logically correct answer.

-The [concurreny](concurrency) sub-directory contains examples of how to use
+The [concurrency](concurrency) sub-directory contains examples of how to use
  Mercury's concurrency interface, i.e. using threads in Mercury programs.

  There are also some sub-directories which contain examples of multi-module
@@ -58,7 +64,7 @@ Mercury programs:
  * [c_interface](c_interface) -- This directory contains some examples of mixed
    Mercury/C/C++/Fortran programs using the C interface.

-* [java_interfac](java_interface) -- This directory contains some examples of
+* [java_interface](java_interface) -- This directory contains some examples of
    mixed Mercury/Java programs using the foreign language interface.

  * [rot13](rot13) -- This directory contains a few implementations of rot-13