Increase description/topic weights by removing the document length compensation.

[isoos]

• This is a follow-up to Increase description weight from 0.9 to 1.0 #8246 in relation with Search results by relevance are wrong  #8139.
• While we have increased the weight in Increase description weight from 0.9 to 1.0 #8246, the overall score of a hit with a non-name match was about 0.97-0.98, while a name match was always 1.0. This is because we have applied the document length compensation in the weight of the description index, and the longer it gets, the more we reduce it, while we don't do anything like that with the name matching.
• While we could have reduced the name scores, I think in this case it is actually better to just skip applying the document weight compensation for the description index (while still keeping it for the readme index).
• The updated test cases show that this is now indeed fixes the ranking difference.