Use weighted average for calculations of the average wpm instead of normal average.

[its-mavi-dev]

Give more weight to the Tests which have more words.
Because 10 words 50wpm and 100 words 50wpm can't be weighted the same for the average wpm calculation.

If you're willing to add this suggestion, then I want to make this code adjustment.
So, can you please guide me to files where I can find the code for it and then implement the weighted formula?