v2doc: core.ignoreStat update, and clarify the --assume-unchanged effect

> The assume-unchanged bit, and consequently core.ignoreStat, can be
> misunderstood. Be assertive about the expectation that file changes should
> notified to Git.
>
> Signed-off-by: Philip Oakley <philipoakley@iee.org>
> ---
> Overhaul the general wording thus:
>     1. direct description of what is ignored given first.
>     2. example instruction of the user manual action required.
>     3. use sideways indirection for assume-unchanged and update-index references.
>     4. add a 'normally' to give leeway for the change detection.
>
> This version is on top of the current master, and replaces the patch in next.

> ---
>  Documentation/config.txt | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index 6862e3e..32e42dd 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -375,13 +375,17 @@ This is useful for excluding servers inside a firewall from
>  proxy use, while defaulting to a common proxy for external domains.
>  
>  core.ignoreStat::
> -	If true, commands which modify both the working tree and the index
> -	will mark the updated paths with the "assume unchanged" bit in the
> -	index. These marked files are then assumed to stay unchanged in the
> -	working tree, until you mark them otherwise manually - Git will not
> -	detect the file changes	by lstat() calls. This is useful on systems
> -	where those are very slow, such as Microsoft Windows.
> -	See linkgit:git-update-index[1].
> +	If true, Git will avoid using lstat() calls to detect if files have
> +	changed. Git will set the "assume-unchanged" bit for those tracked files
> +	which it has updated identically in both the index and working tree.
> ++
> +	When files are modified outside of Git, the user will need to stage
> +	the modified files explicitly (e.g. see 'Examples' section in
> +	linkgit:git-update-index[1]).
> +	Git will not normally detect changes to those files.
> ++
> +	This is useful on systems where lstat() calls are very slow, such as
> +	CIFS/Microsoft Windows.
>  	False by default.
>  
>  core.preferSymlinkRefs::

> Philip Oakley <philipoakley@iee.org> writes:
>
>> The assume-unchanged bit, and consequently core.ignoreStat, can be
>> misunderstood. Be assertive about the expectation that file changes 
>> should
>> notified to Git.
>>
>> Signed-off-by: Philip Oakley <philipoakley@iee.org>
>> ---
>> Overhaul the general wording thus:
>>     1. direct description of what is ignored given first.
>>     2. example instruction of the user manual action required.
>>     3. use sideways indirection for assume-unchanged and update-index 
>> references.
>>     4. add a 'normally' to give leeway for the change detection.
>>
>> This version is on top of the current master, and replaces the patch 
>> in next.
>
> Sorry, you do not replace anything in 'next', once it is in.

>
> I was about to say that I'll try to see if I turn it into
> incremental (at which point some of the above four points after the
> three-dash line might want to be in the log message proper), but the
> AsciiDoc mark-up looks somewhat suspect (we usually do not see
> indentation in the paragraphs continued with "+").  Does this format
> fine for manpage and HTML?

>
> Thanks.
>
>> ---
>>  Documentation/config.txt | 18 +++++++++++-------
>>  1 file changed, 11 insertions(+), 7 deletions(-)
>>
>> diff --git a/Documentation/config.txt b/Documentation/config.txt
>> index 6862e3e..32e42dd 100644
>> --- a/Documentation/config.txt
>> +++ b/Documentation/config.txt
>> @@ -375,13 +375,17 @@ This is useful for excluding servers inside a 
>> firewall from
>>  proxy use, while defaulting to a common proxy for external domains.
>>
>>  core.ignoreStat::
>> - If true, commands which modify both the working tree and the index
>> - will mark the updated paths with the "assume unchanged" bit in the
>> - index. These marked files are then assumed to stay unchanged in the
>> - working tree, until you mark them otherwise manually - Git will not
>> - detect the file changes by lstat() calls. This is useful on systems
>> - where those are very slow, such as Microsoft Windows.
>> - See linkgit:git-update-index[1].
>> + If true, Git will avoid using lstat() calls to detect if files have
>> + changed. Git will set the "assume-unchanged" bit for those tracked 
>> files
>> + which it has updated identically in both the index and working 
>> tree.
>> ++
>> + When files are modified outside of Git, the user will need to stage
>> + the modified files explicitly (e.g. see 'Examples' section in
>> + linkgit:git-update-index[1]).
>> + Git will not normally detect changes to those files.
>> ++
>> + This is useful on systems where lstat() calls are very slow, such 
>> as
>> + CIFS/Microsoft Windows.
>>  False by default.
>>
>>  core.preferSymlinkRefs::
> --