Merge branch 'pb/doc-sequence-editor-configuration'

Doc update.

* pb/doc-sequence-editor-configuration:
  doc: mention GIT_SEQUENCE_EDITOR and 'sequence.editor' more

Documentation/git-rebase.txt

@@ -204,6 +204,7 @@ CONFIGURATION
 -------------
 
 include::config/rebase.txt[]
+include::config/sequencer.txt[]
 
 OPTIONS
 -------

Documentation/git.txt

@@ -605,6 +605,12 @@ other
 	an editor is to be launched. See also linkgit:git-var[1]
 	and the `core.editor` option in linkgit:git-config[1].
 
+`GIT_SEQUENCE_EDITOR`::
+	This environment variable overrides the configured Git editor
+	when editing the todo list of an interactive rebase. See also
+	linkit::git-rebase[1] and the `sequence.editor` option in
+	linkit::git-config[1].
+
 `GIT_SSH`::
 `GIT_SSH_COMMAND`::
 	If either of these environment variables is set then 'git fetch'