doc: add diffMaxChanges and diffTooBigMessage in readme

Author: Pierrci

README.md

@@ -149,6 +149,10 @@ The HTML output accepts a Javascript object with configuration. Possible options
 - `outputFormat`: the format of the output data: `'line-by-line'` or `'side-by-side'`, default is `'line-by-line'`
 - `drawFileList`: show a file list before the diff: `true` or `false`, default is `true`
 - `diffStyle`: show differences level in each line: `word` or `char`, default is `word`
+- `diffMaxChanges`: number of changed lines after which a file diff is deemed as too big and not displayed, default is
+  `undefined`
+- `diffTooBigMessage`: function allowing to customize the message in case of file diff too big (if `diffMaxChanges` is
+  set)
 - `matching`: matching level: `'lines'` for matching lines, `'words'` for matching lines and words or `'none'`, default
   is `none`
 - `matchWordsThreshold`: similarity threshold for word matching, default is `0.25`