Extract the colors defined by editor as vs code custom settings in themes

[sandy081]

Currently editor has feature contributions those define some colors which does not go well with different themes. Extract those colors as vs code custom settings (non standard) in TM themes. This will allow theme writers to provide an appropriate matching color for these features.

Range highlight (Find, Go to line, Go to symbol)

• rangeHighlight

Find / Replace (Find, Search, Reference)

• findMatchHighlight
• currentFindMatchHighlight
• findRangeHighlight

Selection

• inactiveSelection
• selectionHighlight

Words

• wordHighlight
• wordHighlightStrong

Link

• activeLinkForeground

Hover

• hoverHighlight

References

• referenceHighlight

Editor Decorations

[alexdima]

@sandy081 findSelection and findSelectionHighlight look funny, maybe better names would be findMatchHighlight, currentFindMatchHighlight ?