config.txt: move index.* to a separate file

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -355,16 +355,7 @@ include::config/i18n.txt[]
 
 include::config/imap.txt[]
 
-index.threads::
-	Specifies the number of threads to spawn when loading the index.
-	This is meant to reduce index load time on multiprocessor machines.
-	Specifying 0 or 'true' will cause Git to auto-detect the number of
-	CPU's and set the number of threads accordingly. Specifying 1 or
-	'false' will disable multithreading. Defaults to 'true'.
-
-index.version::
-	Specify the version with which new index files should be
-	initialized.  This does not affect existing repositories.
+include::config/index.txt[]
 
 init.templateDir::
 	Specify the directory from which templates will be copied.

Documentation/config/index.txt

@@ -0,0 +1,10 @@
+index.threads::
+	Specifies the number of threads to spawn when loading the index.
+	This is meant to reduce index load time on multiprocessor machines.
+	Specifying 0 or 'true' will cause Git to auto-detect the number of
+	CPU's and set the number of threads accordingly. Specifying 1 or
+	'false' will disable multithreading. Defaults to 'true'.
+
+index.version::
+	Specify the version with which new index files should be
+	initialized.  This does not affect existing repositories.