Document array-accepting manipulation methods

Unit tests which assert this behavior:

- append:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L291
- appendTo:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L506
- prepend:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L607
- prependTo:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L671
- before:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L739
- after:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L291
- insertBefore:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L784
- insertAfter:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L853
- replaceWith:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L988
- replaceAll:
  https://github.com/jquery/jquery/blob/410cf4ee6bd454fa7e2bb5dc37a0b051f15d3e96/test/unit/manipulation.js#L1031