Adding tips to Git to assist with diffs

Git diff often thinks that minor changes are very great changes and does not correctly identify the minor changed code.

Is there a simple way to help git like by adding some marker that is in the source code, or perhaps some other way?

Solution

git diff offers various ways to ignore minor changes:

-w ignores Ignore whitespace when comparing lines
-b ignores space-changes
custom hunk headers to display function headers when detecting a diff.
That is the closest you can add as a tip for git diff, not in the file itself, but in a .gitattributes file.
See for instance "Is there a way to ask git diff to show the method name instead of the class name?".

However, that is for a local diff.
For GitHub, there is no native solution for forcing it to display a diff when the file is "too large".

A similar scenario (still on GitHub) was reported here, when seeing

Sorry, we could not display the entire diff because too many files changed

I'm doing workaround by download the diff file to local, but by that way I don't have the diff highlighting feature like what I got in GitHub PR.