merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/Documentation/git-var.txt

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+git-var(1)
+==========
+
+NAME
+----
+git-var - Show a Git logical variable
+
+
+SYNOPSIS
+--------
+[verse]
+'git var' ( -l | <variable> )
+
+DESCRIPTION
+-----------
+Prints a Git logical variable.
+
+OPTIONS
+-------
+-l::
+	Cause the logical variables to be listed. In addition, all the
+	variables of the Git configuration file .git/config are listed
+	as well. (However, the configuration variables listing functionality
+	is deprecated in favor of `git config -l`.)
+
+EXAMPLES
+--------
+	$ git var GIT_AUTHOR_IDENT
+	Eric W. Biederman <ebiederm@lnxi.com> 1121223278 -0600
+
+
+VARIABLES
+---------
+GIT_AUTHOR_IDENT::
+    The author of a piece of code.
+
+GIT_COMMITTER_IDENT::
+    The person who put a piece of code into Git.
+
+GIT_EDITOR::
+    Text editor for use by Git commands.  The value is meant to be
+    interpreted by the shell when it is used.  Examples: `~/bin/vi`,
+    `$SOME_ENVIRONMENT_VARIABLE`, `"C:\Program Files\Vim\gvim.exe"
+    --nofork`.  The order of preference is the `$GIT_EDITOR`
+    environment variable, then `core.editor` configuration, then
+    `$VISUAL`, then `$EDITOR`, and then the default chosen at compile
+    time, which is usually 'vi'.
+ifdef::git-default-editor[]
+    The build you are using chose '{git-default-editor}' as the default.
+endif::git-default-editor[]
+
+GIT_PAGER::
+    Text viewer for use by Git commands (e.g., 'less').  The value
+    is meant to be interpreted by the shell.  The order of preference
+    is the `$GIT_PAGER` environment variable, then `core.pager`
+    configuration, then `$PAGER`, and then the default chosen at
+    compile time (usually 'less').
+ifdef::git-default-pager[]
+    The build you are using chose '{git-default-pager}' as the default.
+endif::git-default-pager[]
+
+SEE ALSO
+--------
+linkgit:git-commit-tree[1]
+linkgit:git-tag[1]
+linkgit:git-config[1]
+
+GIT
+---
+Part of the linkgit:git[1] suite