Add the character position of a scripting error to error responses.
The contents of the `position` field are experimental and subject to
change. Currently, `offset` refers to the character location where the
error was encountered, `start` and `end` define a range of characters
that contain the error.
eg.
```
{
"error": {
"root_cause": [
{
"type": "script_exception",
"reason": "runtime error",
"script_stack": [
"y = x;",
" ^---- HERE"
],
"script": "def x = new ArrayList(); Map y = x;",
"lang": "painless",
"position": {
"offset": 33,
"start": 29,
"end": 35
}
}
```
Refs: #50993
The example use of a scoring script was incorrectly using a filter
script query, which has no scoring, and thus no _score variable
avialable. This commit converts the example doc to using the newer
script_score query.
* [DOCS] Add template docs to scripts. Reorder template examples.
* Adds a 'Search template' section to the 'How to use scripts' chapter.
This links to the 'Search template' chapter for detailed info and
examples.
* Reorders and retitles several examples in the 'Search template'
chapter. This is primarily to make examples for storing, deleting, and
using search templates more prominent.
* Change <templatename> to <templateid>
Stuart Tettemer
Jack Conradson
Ryan Ernst
James Rodewig