update documentation for add and gitmodules

Author: bicschneider

Documentation/git-add.adoc

@@ -77,7 +77,9 @@ in linkgit:gitglossary[7].
 
 `-f`::
 `--force`::
-	Allow adding otherwise ignored files.
+	Allow adding otherwise ignored files. The option is also used
+	when you update to submodules and `submodule.<name>.ignore=all` 
+	is set.
 
 `--sparse`::
 	Allow updating index entries outside of the sparse-checkout cone.

Documentation/gitmodules.adoc

@@ -70,7 +70,9 @@ 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 --force` similar to ignored files. For `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