Same colour for adjacent numeric columns in DB view

[trantor]

Discussed in https://github.com/tstack/lnav/discussions/1044

As shown in the linked discussion, there are multiple columns marked with the same colour in the DB view in some (cause yet to be determined) situations.

[trantor]

Picking up from the example in #1044 , a bit of debugging led to https://github.com/tstack/lnav/blob/ca4e61ba02345a8b92d846e99fc87de42a707b79/src/view_curses.cc#L1129-L1142

str = user_mid_sum
index = 1400796810
offset = 36

str = user_sum
index = 4009885272
offset = 36

Apparently the algorithm gives the same offset for both strings. Perhaps a second pass to make sure the colours are unique might be in order. (Just an idea).

[tstack]

I think this is fixed, I've also restricted the bars to a given column anyhow. So, the color shouldn't matter as much.