githooks.txt: improve the intro section

Change the documentation so that:

 * We don't talk about "little scripts". Hooks can be as big as you
   want, and don't have to be scripts, just call them "programs".

 * We note that we change the working directory before a hook is called,
   nothing documented this explicitly, but the current behavior is
   predictable. It helps a lot to know what directory these hooks will
   be executed from.

 * We don't make claims about the example hooks which may not be true
   depending on the configuration of 'init.templateDir'. Clarify that
   we're talking about the default settings of git-init in those cases,
   and move some of this documentation into git-init's documentation
   about the default templates.

 * We briefly note in the intro that hooks can get their arguments in
   various different ways, and that how exactly is described below for
   each hook.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/Documentation/git-init.txt b/Documentation/git-init.txt
index 8174d27..6364e5d 100644
--- a/Documentation/git-init.txt
+++ b/Documentation/git-init.txt
@@ -130,7 +130,12 @@ The template directory will be one of the following (in order):
  - the default template directory: `/usr/share/git-core/templates`.
 
 The default template directory includes some directory structure, suggested
-"exclude patterns" (see linkgit:gitignore[5]), and sample hook files (see linkgit:githooks[5]).
+"exclude patterns" (see linkgit:gitignore[5]), and sample hook files.
+
+The sample hooks are all disabled by default, To enable one of the
+sample hooks rename it by removing its `.sample` suffix.
+
+See linkgit:githooks[5] for more general info on hook execution.
 
 EXAMPLES
 --------