Descendant selector semantics

[glyn]

• Exclude the node itself
• Define the term "descendants" more precisely
• Define the descendant selector semantics more thoroughly

Fixes: https://github.com/ietf-wg-jsonpath/draft-ietf-jsonpath-base/issues/177

[bram209]

I would consider adding two additional examples:

given:

{
  "j":  10,
  "o": {"j": 11, "k": 2},
  "a": [
     { "j": [3, 5] },
     { "j": [4, 6] }
  ]
}

$..[0] results in:

• { "j": [3, 5] }
• 3
• 4

$..j and $..['j'] results in:

• 10
• 11
• [3, 5]

• [4, 6]

[glyn]

I would consider adding two additional examples:

given:

{
  "j":  10,
  "o": {"j": 11, "k": 2},
  "a": [
     { "j": [3, 5] },
     { "j": [4, 6] }
  ]
}

$..[0] results in:

* `{ "j": [3, 5] }`

* `3`

* `4`

$..j and $..['j'] results in:

* `10`

* `11`

* `[3, 5`]

* `[4, 6`]

I extended the existing example attempting to exhibit the same points as the example above.

[bram209]

I extended the existing example attempting to exhibit the same points as the example above.

Looks good, thanks!