Row Pinning feature, example, and docs

[KevinVandy]

This PR adds Row Pinning functionality to TanStack Table, in addition to the column pinning functionality already present.

Most changes to table-core are confined to Pinning.ts, with a couple more tweaks to solve edge cases needed in Expanding.ts and table.ts
 
New Table State:

rowPinning: { top?: string[], bottom?: string[] }

New Table Options:

enableColumnPinning?: boolean //distinguish from `enablePinning` (still backwards compat)
onRowPinningChange?: OnChangeFn<RowPinningState>
enableRowPinning?: boolean | ((row: Row<TData>) => boolean)
keepPinnedRows?: boolean

New Table APIs:

setRowPinning: (updater: Updater<RowPinningState>) => void
resetRowPinning: (defaultState?: boolean) => void
getIsSomeRowsPinned: (position?: RowPinningPosition) => boolean
_getPinnedRows: (position: 'top' | 'bottom') => Row<TData>[]
getTopRows: () => Row<TData>[]
getBottomRows: () => Row<TData>[]
getCenterRows: () => Row<TData>[]

New Row APIs:

getCanPin: () => boolean
getIsPinned: () => RowPinningPosition
getPinnedIndex: () => number
pin: (
  position: RowPinningPosition,
  includeLeafRows?: boolean,
  includeParentRows?: boolean
) => void
getIsAllParentsExpanded: () => boolean

Caveats

table.getRow was tweaked to allow for finding rows from table.getCoreRowModel() instead of the default table.getRowModel

The compiled size of TanStack Table Core increases from 13.9 kb to 14.3 kb

[tannerlinsley]

Seems useful and a core concern. I’m good to include it.