fix punctuation

[Nightblade]

two very minor punctuation fixes (blame QuickStick for finding them!)

[QuickStick123]

Probably capatilise the i and there is anouther lowcase i and incorrect capalisation after full stop. line 611 of TreeTab "-- especially given the heatmap's current approach of using the sqrt() of both components. that number is cryptic to users, i suspect."