Merge branch 'jk/color-diff-plain-is-context' into maint

"color.diff.plain" was a misnomer; give it 'color.diff.context' as
a more logical synonym.

* jk/color-diff-plain-is-context:
  diff.h: rename DIFF_PLAIN color slot to DIFF_CONTEXT
  diff: accept color.diff.context as a synonym for "plain"

diff --cc Documentation/config.txt
index f4fb31a08d89ce0f753a27f9d00fc4d769e3f297,b458590f26b56084348a9d392007070007f39f5b..2e919f0df8c13b31cbea45690d2677809116bf88
--- 1/Documentation/config.txt
--- 2/Documentation/config.txt
+++ b/Documentation/config.txt
@@@ -906,10 -870,12 +906,11 @@@ command line with the `--color[=<when>]
  color.diff.<slot>::
        Use customized color for diff colorization.  `<slot>` specifies
        which part of the patch to use the specified color, and is one
-       of `plain` (context text), `meta` (metainformation), `frag`
+       of `context` (context text - `plain` is a historical synonym),
+       `meta` (metainformation), `frag`
        (hunk header), 'func' (function in hunk header), `old` (removed lines),
        `new` (added lines), `commit` (commit headers), or `whitespace`
 -      (highlighting whitespace errors). The values of these variables may be
 -      specified as in color.branch.<slot>.
 +      (highlighting whitespace errors).
  
  color.decorate.<slot>::
        Use customized color for 'git log --decorate' output.  `<slot>` is one

diff --cc diff.c
Simple merge

diff --cc line-log.c
Simple merge