docs: move index format docs to man section 5

Continue the move of existing Documentation/technical/* protocol and
file-format documentation into our main documentation space by moving
the index format documentation.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/Makefile

@@ -26,6 +26,7 @@ MAN1_TXT += gitweb.txt
 MAN5_TXT += gitattributes.txt
 MAN5_TXT += gitformat-bundle.txt
 MAN5_TXT += gitformat-commit-graph.txt
+MAN5_TXT += gitformat-index.txt
 MAN5_TXT += githooks.txt
 MAN5_TXT += gitignore.txt
 MAN5_TXT += gitmailmap.txt
@@ -104,7 +105,6 @@ TECH_DOCS += technical/bitmap-format
 TECH_DOCS += technical/cruft-packs
 TECH_DOCS += technical/hash-function-transition
 TECH_DOCS += technical/http-protocol
-TECH_DOCS += technical/index-format
 TECH_DOCS += technical/long-running-process-protocol
 TECH_DOCS += technical/multi-pack-index
 TECH_DOCS += technical/pack-format

Documentation/gitformat-index.txt

@@ -1,5 +1,19 @@
+gitformat-index(5)
+==================
+
+NAME
+----
+gitformat-index - Git index format
+
+SYNOPSIS
+--------
+[verse]
+$GIT_DIR/index
+
+DESCRIPTION
+-----------
+
 Git index format
-================
 
 == The Git index file has the following format
 
@@ -404,3 +418,7 @@ The remaining data of each directory block is grouped by type:
   with signature { 's', 'd', 'i', 'r' }. Like the split-index extension,
   tools should avoid interacting with a sparse index unless they understand
   this extension.
+
+GIT
+---
+Part of the linkgit:git[1] suite

command-list.txt

@@ -211,6 +211,7 @@ giteveryday                             guide
 gitfaq                                  guide
 gitformat-bundle                        developerinterfaces
 gitformat-commit-graph                  developerinterfaces
+gitformat-index                         developerinterfaces
 gitglossary                             guide
 githooks                                userinterfaces
 gitignore                               userinterfaces