gitattributes-mode: Major mode for editing .gitattributes files.

Initial release.  So far it supports some basic syntax highlighting.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Updated README.md: Add gitattributes-mode.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Remove use of `rx'.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Add forward-field operation.

Sets `forward-sexp-function' to `gitattributes-mode-forward-field' to
treat fields as "sexps".  Also add a menu.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Add function to open manpage.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Add ElDoc support.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Highlight macro keyword.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Improve highlight.

Add highlight for pattern similar to `gitignore-mode'.  Highlight for
/ is missing (TODO).  Highlight for variables fixed (includes - now,
e.g., for "export-ignore").  Highlight for "[attr]" changed to
`font-lock-function-name-face'.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
gitattributes: Provide easy way (default) to enable eldoc.

* gitattributes-mode.el (gitattributes-mode-enable-eldoc):  New
  Variable.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Merge pull request #34 from ruediger/gitattributes-mode

gitattributes-mode: Major mode for editing .gitattributes files.