Format generated Go code to adhere to golang coding standards

[firefart]

Golang expects generated code to be properly go fmt'ed (see golang/go#73181 (comment)).

This PR tries to implement the changes so the code will be compatible and go fmt will not change anything in the generated code.

Changes:

• indent using tabs instead of spaces
• when there is only one return argument, omit the parentheses
• removes trailing spaces on comments without a content
• fix import ordering
• correctly indent case statements inside a switch

Test:
To test we will create a test client. Next go to the golangtest directory, init a git repo, and run go fmt to see the differences

rm -rf ./golangtest/ && cp -r ./it/go golangtest && dotnet build && ./src/kiota/bin/Debug/net10.0/kiota generate --openapi https://aka.ms/graph/v1.0/openapi.yaml --output ./golangtest/client --language go --exclude-backward-compatible --clean-output -i '/groups/getByIds#POST' -n 'integrationtest/client'
cd golangtest
git init
git add .
go fmt ./...
git diff

Ideally the git diff will show no changes

[baywet]

Thanks for the contribution!

[Copilot]

Pull request overview

This PR updates the Go code generator to better match gofmt expectations (tabs for indentation, Go-style return type formatting, cleaner comments, import ordering, and switch/case indentation) so go fmt produces no diffs on generated output.

Changes:

• Switch Go generation indentation to tabs (via LanguageWriter + GoWriter).
• Adjust Go signatures/returns/comment formatting to align with gofmt conventions.
• Update Go writer logic and tests around imports, switch/case indentation, and return type formatting.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
tests/Kiota.Builder.Tests/Writers/Go/CodeMethodWriterTests.cs	Updates assertions to match new Go formatting expectations.
src/Kiota.Builder/Writers/LanguageWriter.cs	Adds configurable indentation character/size to support tabs for Go.
src/Kiota.Builder/Writers/Go/GoWriter.cs	Configures Go writer to use tab indentation.
src/Kiota.Builder/Writers/Go/GoNamespaceExtensions.cs	Simplifies namespace import string concatenation.
src/Kiota.Builder/Writers/Go/GoConventionService.cs	Adjusts doc comment prefix handling to avoid trailing spaces.
src/Kiota.Builder/Writers/Go/CodeProprietableBlockDeclarationWriter.cs	Changes import ordering/format in type declarations.
src/Kiota.Builder/Writers/Go/CodePropertyWriter.cs	Avoids emitting trailing spaces for typeless/embedded fields.
src/Kiota.Builder/Writers/Go/CodeMethodWriter.cs	Refactors Go method prototype emission, removes semicolons, adjusts spacing/blocks.
src/Kiota.Builder/Writers/Go/CodeInterfaceDeclarationWriter.cs	Removes redundant string interpolation in output.
src/Kiota.Builder/Writers/Go/CodeFileDeclarationWriter.cs	Changes import ordering/format at file scope.
src/Kiota.Builder/Writers/Go/CodeEnumWriter.cs	Refactors enum parsing switch generation for gofmt-style indentation.
src/Kiota.Builder/Writers/Go/CodeClassDeclarationWriter.cs	Removes redundant string interpolation in output.
src/Kiota.Builder/Refiners/GoRefiner.cs	Updates deserializer function return type formatting.
it/go/app.go	Reorders imports/indentation in Go integration test app.
CHANGELOG.md	Adds changelog entries for the Go formatting changes (and adjusts some older formatting).
.devcontainer/devcontainer.json	Updates recommended VS Code extensions in devcontainer configuration.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated 1 comment.

[firefart]

@baywet sorry for the long silence, I totally forgot about this open PR. I just added the missing tests. Please let me know if you need anything else on this to get it ready