Merge branch 'dg/document-git-c-in-git-config-doc' into maint

The "git -c var[=val] cmd" facility to append a configuration
variable definition at the end of the search order was described in
git(1) manual page, but not in git-config(1), which was more likely
place for people to look for when they ask "can I make a one-shot
override, and if so how?"

* dg/document-git-c-in-git-config-doc:
  doc: mention `git -c` in git-config(1)

diff --cc Documentation/git-config.txt
index f163113a6faafa675d921381447bd83aaa8e1708,636b3eb47887b5feca76c25bbdac9e7e666b799d..83f86b9231b012bbb4716dc27cd72291cb48126a
--- 1/Documentation/git-config.txt
--- 2/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@@ -263,13 -263,16 +263,16 @@@ The files are read in the order given a
  precedence over values read earlier.  When multiple values are taken then all
  values of a key from all files will be used.
  
+ You may override individual configuration parameters when running any git
+ command by using the `-c` option. See linkgit:git[1] for details.
+ 
  All writing options will per default write to the repository specific
 -configuration file. Note that this also affects options like '--replace-all'
 -and '--unset'. *'git config' will only ever change one file at a time*.
 +configuration file. Note that this also affects options like `--replace-all`
 +and `--unset`. *'git config' will only ever change one file at a time*.
  
  You can override these rules either by command-line options or by environment
 -variables. The '--global' and the '--system' options will limit the file used
 -to the global or system-wide file respectively. The GIT_CONFIG environment
 +variables. The `--global` and the `--system` options will limit the file used
 +to the global or system-wide file respectively. The `GIT_CONFIG` environment
  variable has a similar effect, but you can specify any filename you want.