Fix hover on const in as const to display the specific type

[Copilot]

Hovering on const in 42 as const showed type const instead of type const = 42.

The SymbolFlagsTypeAlias branch in getQuickInfoAndDeclarationAtLocation guarded the type display with if len(symbol.Declarations) != 0. The const keyword in as const resolves to an intrinsic type alias symbol with no declarations, so the type was never printed.

• Removed the declarations length guard, matching the TypeScript source (symbolDisplay.ts) which unconditionally writes = <type> for type aliases
• The existing IsConstTypeReference check already correctly resolves the type via GetTypeAtLocation(node.Parent)

const foo = 42 as const
//                ^^^^^ was: "type const", now: "type const = 42"

[Copilot]

Pull request overview

Fixes Language Service hover output for the const keyword in as const assertions so it shows the resolved literal/specific type (e.g. type const = 42) rather than only type const. This aligns the Go port’s type-alias quick info formatting with upstream TypeScript behavior and is validated via updated fourslash baselines plus a focused regression test.

Changes:

• Updated getQuickInfoAndDeclarationAtLocation to always append = <type> for SymbolFlagsTypeAlias quick info (no longer gated on len(symbol.Declarations) != 0).
• Kept/leveraged the existing IsConstTypeReference path to resolve the asserted type via GetTypeAtLocation(node.Parent) for as const.
• Added/updated fourslash coverage (new targeted test + updated reference baseline).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/ls/hover.go	Always emits type <alias> = <type> for type-alias quick info; ensures as const’s intrinsic alias renders the asserted type.
testdata/baselines/reference/fourslash/quickInfo/quickInfoForConstAssertions.baseline	Updates expected hover output for as const markers to include = <specific type>.
internal/fourslash/tests/quickInfoConstAssertion_test.go	Adds a focused regression test asserting hover on const in 42 as const shows type const = 42.