Clang-format: allow -style="{yaml/json}" on command line

Summary: + improved handling of default style and predefined styles.

Reviewers: djasper, klimek

Reviewed By: klimek

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D813

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182205 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ClangFormat.rst b/docs/ClangFormat.rst
index a9687bc..8df7d24 100644
--- a/docs/ClangFormat.rst
+++ b/docs/ClangFormat.rst
@@ -20,8 +20,8 @@
 
   If no arguments are specified, it formats the code from standard input
   and writes the result to the standard output.
-  If <file>s are given, it reformats the files. If -i is specified
-  together with <file>s, the files are edited in-place. Otherwise, the
+  If <file>s are given, it reformats the files. If -i is specified 
+  together with <file>s, the files are edited in-place. Otherwise, the 
   result is written to the standard output.
 
   USAGE: clang-format [options] [<file> ...]
@@ -47,10 +47,13 @@
     -output-replacements-xml - Output replacements as XML.
     -style=<string>          - Coding style, currently supports:
                                  LLVM, Google, Chromium, Mozilla.
-                               Use '-style file' to load style configuration from
+                               Use -style=file to load style configuration from
                                .clang-format file located in one of the parent
                                directories of the source file (or current
                                directory for stdin).
+                               Use -style="{key: value, ...}" to set specific
+                               parameters, e.g.:
+                                 -style="{BasedOnStyle: llvm, IndentWidth: 8}"
 
   General options: