search: expose parse tree via GQL [3/3]

Created by: rvantonder

Stacked on #11773.

This PR introduces the endpoint that exposes the query parse tree via GQL for web/query input applications. It's not ready yet the way I want it, but nevertheless returns the current parse tree data of a processed query. No tests: this is an experimental endpoint and the spec isn't fixed yet.

CC @lguychard @attfarhan: let me know if the choice of capitalization in the JSON output works for you (all fields lowercase, I debated making operator names capitalized, like AND or OR, but decided against it for consistency's sake).

expand for current example JSON format

query {
  parseSearchQuery(
    query: "repo:foo file:bar b.*z or qux", 
    patternType: regexp
  )
}

[
  {
    "and": [
      {
        "field": "repo",
        "value": "foo",
        "negated": false,
        "range": {
          "start": {
            "line": 0,
            "column": 0
          },
          "end": {
            "line": 0,
            "column": 8
          }
        }
      },
      {
        "field": "file",
        "value": "bar",
        "negated": false,
        "range": {
          "start": {
            "line": 0,
            "column": 9
          },
          "end": {
            "line": 0,
            "column": 17
          }
        }
      },
      {
        "or": [
          {
            "value": "b.*z",
            "negated": false,
            "labels": [
              "HeuristicHoisted"
            ],
            "range": {
              "start": {
                "line": 0,
                "column": 18
              },
              "end": {
                "line": 0,
                "column": 23
              }
            }
          },
          {
            "value": "qux",
            "negated": false,
            "labels": [
              "HeuristicHoisted",
              "HeuristicParensAsPatterns",
              "Literal"
            ],
            "range": {
              "start": {
                "line": 0,
                "column": 26
              },
              "end": {
                "line": 0,
                "column": 29
              }
            }
          }
        ]
      }
    ]
  }
]

---

TODOs before it's 'ready for use', I need to update the following in the internals in separate PRs:

• I remove the top-level list that encloses the query. This requires a deeper refactoring so that nodes are always rooted with an operator. The current convention allows a possibly flat list of parameters (i.e., multiple roots) for flat queries, and I'd like to change that convention.

• I need to still describe a spec of the JSON for including (1) the parse tree of the processed/transformed query (which we might produce when simplifying the query) (2) the parse tree of the raw query, and the possibly (3) alternative suggestions for the query in ambiguous cases. The endpoint currently exposes only (1).

• Improving labels for (regex operators, better labels).

Created by: codecov[bot]

Codecov Report

Merging #11776 into rvt/record-ranges-for-literal-parser will decrease coverage by 0.17%. The diff coverage is 81.81%.

@@                           Coverage Diff                            @@
##           rvt/record-ranges-for-literal-parser   #11776      +/-   ##
========================================================================
- Coverage                                 47.86%   47.69%   -0.18%     
========================================================================
  Files                                      1402     1402              
  Lines                                     80032    79768     -264     
  Branches                                   6675     6686      +11     
========================================================================
- Hits                                      38309    38042     -267     
- Misses                                    38138    38152      +14     
+ Partials                                   3585     3574      -11     

Flag	Coverage Δ
#go	51.85% <81.81%> (-0.23%)
#storybook	10.11% <ø> (ø)
#typescript	36.61% <ø> (ø)
#unit	47.29% <81.81%> (-0.18%)

Impacted Files	Coverage Δ
cmd/frontend/graphqlbackend/search_results.go	42.41% <0.00%> (ø)
internal/search/query/mapper.go	92.30% <62.50%> (ø)
internal/search/query/literal_parser.go	88.94% <94.44%> (+0.38%)
internal/search/query/transformer.go	98.49% <100.00%> (ø)
enterprise/internal/codeintel/store/store.go	59.64% <0.00%> (-9.67%)
...terprise/internal/codeintel/store/observability.go	92.07% <0.00%> (-6.16%)
...ntel-bundle-manager/internal/janitor/db_records.go	52.45% <0.00%> (-4.84%)
...e-intel-bundle-manager/internal/janitor/janitor.go	4.16% <0.00%> (-3.25%)
enterprise/internal/codeintel/store/uploads.go	89.89% <0.00%> (-2.27%)
enterprise/internal/codeintel/store/indexes.go	92.79% <0.00%> (-0.07%)

Created by: rvantonder

@attfarhan or @sourcegraph/search feel free to approve if this seems fine to you. I do not anticipate changing the GQL endpoint (just the exact JSON schema needs to be pinned down, but this is not blocking for this PR).