[PATCH v2] Documentation: declare "core.ignorecase" as internal variable

[Marc Strapetz <marc.strapetz@syntevo.com>]

The current description of "core.ignoreCase" reads like an option which
is intended to be changed by the user while it's actually expected to
be set by Git on initialization only. This is especially important for
Git for Windows, as noted by Bryan Turner [1]:

     Git on Windows is not designed to run with anything other than
     core.ignoreCase=true, and attempting to do so will cause
     unexpected behavior. In other words, it's not a behavior toggle so
     user's can request the functionality to work one way or the other;
     it's an implementation detail that `git init` and `git clone` set
     when a repository is created purely so they don't have to probe
     the file system each time you run a `git` command.

[1] https://marc.info/?l=git&m=152972992729761&w=2

Signed-off-by: Marc Strapetz <marc.strapetz@syntevo.com>
---
  Documentation/config.txt | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab641bf5a..c25693828 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -390,7 +390,7 @@ core.hideDotFiles::
  	default mode is 'dotGitOnly'.

  core.ignoreCase::
-	If true, this option enables various workarounds to enable
+	Internal variable which enables various workarounds to enable
  	Git to work better on filesystems that are not case sensitive,
  	like FAT. For example, if a directory listing finds
  	"makefile" when Git expects "Makefile", Git will assume
@@ -399,7 +399,7 @@ core.ignoreCase::
  +
  The default is false, except linkgit:git-clone[1] or linkgit:git-init[1]
  will probe and set core.ignoreCase true if appropriate when the repository
-is created.
+is created. Modifying this value afterwards may result in unexpected 
behavior.

  core.precomposeUnicode::
  	This option is only used by Mac OS implementation of Git.
-- 
2.17.0.rc0.3.gb1b5a51b2