Remove contrib/examples/*

There were some side discussions at Git Merge this year about how we
should just update the README to tell users they can dig these up from
the history if the need them, do that.

Looking at the "git log" for this directory we get quite a bit more
patch churn than we should here, mainly from things fixing various
tree-wide issues.

There's also confusion on the list occasionally about how these should
be treated, "Re: [PATCH 1/4] stash: convert apply to
builtin" (<CA+CzEk9QpmHK_TSBwQfEedNqrcVSBp3xY7bdv1YA_KxePiFeXw@mail.gmail.com>)
being the latest example of that.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

contrib/examples/README

@@ -1,3 +1,20 @@
-These are original scripted implementations, kept primarily for their
-reference value to any aspiring plumbing users who want to learn how
-pieces can be fit together.
+This directory used to contain scripted implementations of builtins
+that have since been rewritten in C.
+
+They have now been removed, but can be retrieved from an older commit
+that removed them from this directory.
+
+They're interesting for their reference value to any aspiring plumbing
+users who want to learn how pieces can be fit together, but in many
+cases have drifted enough from the actual implementations Git uses to
+be instructive.
+
+Other things that can be useful:
+
+ * Some commands such as git-gc wrap other commands, and what they're
+   doing behind the scenes can be seen by running them under
+   GIT_TRACE=1
+
+ * Doing `git log` on paths matching '*--helper.c' will show
+   incremental effort in the direction of moving existing shell
+   scripts to C.