[PATCH] doc: make the gitfile syntax easier to discover

[Marcel Krause <mk+copyleft@pimpmybyte.de>]

It took way too long for me to find the syntax expected for a gitfile.
My search engine found the gitglossary manpage which defined the term
but had no hints about syntax.
Thus here I add a mention of gitrepository-layout.

Once I somehow found gitrepository-layout, I searched for "gitfile" in
there, but had no matches. It took a moment of discouragement and a
minute or so of actually reading to find the info I was looking for.
Thus here I add the part "[This mechanism is] called a 'gitfile'" in
hopes that future readers will find it in mere seconds and without
discouragement. Maybe it even helps search engines find it.

Ideally, someone else may add a mention of gitrepository-layout in the
"fatal: invalid gitfile format:" error message, which is what sent me
on my journey initially, or even add a stub man page named "gitfile".

Based on the maint branch for maximum compatibility.

Signed-off-by: Marcel Krause <mk+copyleft@pimpmybyte.de>
---
 Documentation/gitrepository-layout.txt | 8 ++++----
 Documentation/glossary-content.txt     | 1 +
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/Documentation/gitrepository-layout.txt b/Documentation/gitrepository-layout.txt
index 1a2ef4c150..c52b8564e3 100644
--- a/Documentation/gitrepository-layout.txt
+++ b/Documentation/gitrepository-layout.txt
@@ -23,10 +23,10 @@ A Git repository comes in two different flavours:
 
 *Note*: Also you can have a plain text file `.git` at the root of
 your working tree, containing `gitdir: <path>` to point at the real
-directory that has the repository.  This mechanism is often used for
-a working tree of a submodule checkout, to allow you in the
-containing superproject to `git checkout` a branch that does not
-have the submodule.  The `checkout` has to remove the entire
+directory that has the repository.  This mechanism is called a 'gitfile'
+and is often used for a working tree of a submodule checkout, to allow
+you in the containing superproject to `git checkout` a branch that
+does not have the submodule.  The `checkout` has to remove the entire
 submodule working tree, without losing the submodule repository.
 
 These things may exist in a Git repository.
diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt
index 5a537268e2..e5f55bf670 100644
--- a/Documentation/glossary-content.txt
+++ b/Documentation/glossary-content.txt
@@ -184,6 +184,7 @@ current branch integrates with) obviously do not work, as there is no
 [[def_gitfile]]gitfile::
 	A plain file `.git` at the root of a working tree that
 	points at the directory that is the real repository.
+	See linkgit:gitrepository-layout for the syntax.
 
 [[def_grafts]]grafts::
 	Grafts enables two otherwise different lines of development to be joined
-- 
2.25.1