Use correct default value (#14949)

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -761,7 +761,7 @@ NB: You must have `DISABLE_ROUTER_LOG` set to `false` for this option to take ef
 
 - `PATH`: **""**: The path of git executable. If empty, Gitea searches through the PATH environment.
 - `DISABLE_DIFF_HIGHLIGHT`: **false**: Disables highlight of added and removed changes.
-- `MAX_GIT_DIFF_LINES`: **100**: Max number of lines allowed of a single file in diff view.
+- `MAX_GIT_DIFF_LINES`: **1000**: Max number of lines allowed of a single file in diff view.
 - `MAX_GIT_DIFF_LINE_CHARACTERS`: **5000**: Max character count per line highlighted in diff view.
 - `MAX_GIT_DIFF_FILES`: **100**: Max number of files shown in diff view.
 - `COMMITS_RANGE_SIZE`: **50**: Set the default commits range size