fix: completion for strings with trigger character

[DeMoorJasper]

Pull Request

When trying to type a string with a trigger character the autocompletion does not return a testEdit, causing editors to append the text resulting in duplication and unwanted behaviour.

Explanation

Had a completion result with the following content:

{
   "name": "hello/world",
   "kind": "string",
   "kindModifiers": "",
   "sortText": "11",
   "replacementSpan": {
      "start": {
         "line": 9,
         "offset": 11
      },
      "end": {
         "line": 9,
         "offset": 12
      }
   }
}

Got transformed into:

{
   "label":"hello/world",
   "kind":21,
   "sortText":"11",
   "data":{
      "file":"/Users/jasper/projects/codesandbox/pitcher/packages/pitcher-agent/workspace/codesandbox/test-sandbox/draft/priceless-curran/pages/_app.tsx",
      "line":9,
      "offset":12,
      "entryNames":[
         "hello/world"
      ]
   }
}

But the correct one is:

{
   "label":"hello/world",
   "kind":21,
   "sortText":"11",
   "data":{
      "file":"/Users/jasper/projects/codesandbox/pitcher/packages/pitcher-agent/workspace/codesandbox/test-sandbox/draft/priceless-curran/pages/_app.tsx",
      "line":9,
      "offset":12,
      "entryNames":[
         "hello/world"
      ]
   },
   "textEdit":{
      "range":{
         "start":{
            "line":8,
            "character":10
         },
         "end":{
            "line":8,
            "character":11
         }
      },
      "newText":"hello/world"
   }
}

Code to reproduce this:

function test(value: "fs/read" | "hello/world") {
  return true;
}

test("fs/")

When the cursor is after test("fs/ and tries to autocomplete it fails causing test("fs/fs/read") instead of test("fs/read")

[rchl]

This part doesn't really seem relevant to fixing the issue but it's good to have nonetheless.

[rchl]

Thanks!