Documentation: add --include_ignored_submodules + ignore=all config

- git-add.adoc: Add new documentation for --include_ignored_submodules
  option to supress ignore=all and new submodule functionality of not
  adding a ignore=all submodule by default.
- gitmodules.adoc and config/submodule.adoc: The submodule config
  ignore=all now need --include_ignored_submodules in order to update
  the index.

Signed-off-by: Claus Schneider(Eficode) <claus.schneider@eficode.com>

Author: bicschneider

Documentation/config/submodule.adoc

@@ -32,15 +32,16 @@ submodule.<name>.fetchRecurseSubmodules::
 
 submodule.<name>.ignore::
 	Defines under what circumstances "git status" and the diff family show
-	a submodule as modified. When set to "all", it will never be considered
-	modified (but it will nonetheless show up in the output of status and
-	commit when it has been staged), "dirty" will ignore all changes
-	to the submodule's work tree and
-	takes only differences between the HEAD of the submodule and the commit
-	recorded in the superproject into account. "untracked" will additionally
+	a submodule as modified. 
+	Set to "all" will never considered the submodule modified. It can 
+	nevertheless be staged using the option --include_ignored_submodules and
+	it will then show up in the output of status.
+	Set to "dirty" will ignore all changes to the submodule's work tree and 
+	takes only differences between the HEAD of the submodule and the commit 
+	recorded in the superproject into account. "untracked" will additionally 
 	let submodules with modified tracked files in their work tree show up.
-	Using "none" (the default when this option is not set) also shows
-	submodules that have untracked files in their work tree as changed.
+	Set to "none"(default) It is also shows submodules that have untracked 
+	files in their work tree as changed.
 	This setting overrides any setting made in .gitmodules for this submodule,
 	both settings can be overridden on the command line by using the
 	"--ignore-submodules" option. The 'git submodule' commands are not

Documentation/git-add.adoc

@@ -79,6 +79,11 @@ in linkgit:gitglossary[7].
 `--force`::
 	Allow adding otherwise ignored files.
 
+`--include_ignored_submodules`::
+	The option is also used when `submodule.<name>.ignore=all`
+	is set, but you want to stage an update of the submodule. The 
+	`path` to the submodule must be explicitly specified.
+
 `--sparse`::
 	Allow updating index entries outside of the sparse-checkout cone.
 	Normally, `git add` refuses to update index entries whose paths do

Documentation/gitmodules.adoc

@@ -70,7 +70,10 @@ submodule.<name>.ignore::
 --
 	all;; The submodule will never be considered modified (but will
 	    nonetheless show up in the output of status and commit when it has
-	    been staged).
+	    been staged). Add `(new commits)` can be overruled using the
+	    `git add --include_ignored_submodules <submodule.path>` 
+		The setting affects `status`, `update-index`, `diff` and `log`(due 
+		to underlaying `diff`).
 
 	dirty;; All changes to the submodule's work tree will be ignored, only
 	    committed differences between the `HEAD` of the submodule and its