docs: Adjust Gravsearch documentation according to current state of code (DEV-2153)

[BalduinLandolt]

Pull Request Checklist

Task Description/Number

Issue Number: DEV-

PR Type

• build/chore: maintenance tasks (no production code change)
• docs: documentation changes (no production code change)
• feat: represents new features
• fix: represents bug fixes
• perf: performance improvements
• refactor: represents production code refactoring
• test: adding or refactoring tests (no production code change)

Basic requirements for bug fixes and features

• Tests for the changes have been added
• Docs have been added / updated

Does this PR introduce a breaking change?

• Yes

Does this PR change client-test-data?

• Yes

[linear]

DEV-2153 Adjust Docs according to changed structure of gravsearch

[codecov]

Codecov Report

Attention: 69 lines in your changes are missing coverage. Please review.

Comparison is base (ff9df5f) 11.63% compared to head (0c11531) 11.64%.
Report is 8 commits behind head on main.

Files	Patch %	Lines
...s/v2/responder/valuemessages/ValueMessagesV2.scala	0.00%	22 Missing ⚠️
.../org/knora/webapi/store/iiif/api/SipiService.scala	0.00%	9 Missing ⚠️
...vsearch/types/GravsearchTypeInspectionRunner.scala	0.00%	8 Missing ⚠️
...knora/webapi/store/iiif/impl/SipiServiceLive.scala	0.00%	5 Missing ⚠️
...ra/webapi/responders/v2/ResourcesResponderV2.scala	0.00%	4 Missing ⚠️
...c/main/scala/org/knora/webapi/core/AppServer.scala	0.00%	2 Missing ⚠️
...earch/mainquery/GravsearchMainQueryGenerator.scala	0.00%	2 Missing ⚠️
...vsearch/prequery/GravsearchQueryOptimisation.scala	0.00%	2 Missing ⚠️
...rch/prequery/GravsearchToPrequeryTransformer.scala	0.00%	2 Missing ⚠️
...ora/webapi/responders/admin/SipiResponderADM.scala	0.00%	2 Missing ⚠️
... and 8 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2938      +/-   ##
==========================================
+ Coverage   11.63%   11.64%   +0.01%     
==========================================
  Files         247      246       -1     
  Lines       22922    22885      -37     
==========================================
- Hits         2668     2666       -2     
+ Misses      20254    20219      -35     

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