Clean up correlation docs

Copies the documentation technique used for DateFrequency, to avoid our
docs listing methods as insight.correlation.correlation.fromValues.
Fix DataSet param comment

Copy-paste error, the description was wrong.
Remove Dimension @todos

These are now in Jira as ICS-246 and ICS-247
Remove insight.Dimension from docs

This class is only used internally, so should not clutter the docs.
Use @link for linear line type

We already used an address, but JSDocs needs to be told that it should
be a link. We now properly link, and hide it behind a link caption.
Use @link between docs pages

Links the Axis.tickLabelFormat to the insight.Formatters.
Be explicit about DataSet in series constructor

Clarifies that this is supposed to be an insight type.
Remove optional from addX/YAxis
Add missing type to setInteractiveAxis

While it is heavily implied that setInteractiveAxis takes an axis, we
should be explicit!
Return {this} for Table asc/desc

The comments already said we returned {this}, but now we match the rest
of the documentation.
Add internal links to Table.top

Links to ascending/descending
Tidy up Tooltip docs

Adds in examples for the tooltip style, and properly groups methods into
internal/private/public methods/vars
Remove colour from RowSeries

We don't use the colour anymore, so shouldn't document it.
Use @link and @see for Series.tooltipFormat
Updates Tooltip to use @example

We were already saying "E.g.", might as well use an @example tag
Adds Chart.margin examples
Use @example in Chart constructor
Use @example for Table constructor
Use @example for Table.columns
Merge branch 'upstream' into develop