cmd/compile: include generic type when reporting inline function from go compiler

[Kentzo]

What version of Go, VS Code & VS Code Go extension are you using?

Version Information

• Run go version to get version of Go from the VS Code integrated terminal.
  • go version go1.26.3 darwin/arm64
• Run gopls -v version to get version of Gopls from the VS Code integrated terminal.
  • golang.org/x/tools/gopls v0.22.0
• Run code -v or code-insiders -v to get version of VS Code or VS Code Insiders.
  • 1.126.0
• Check your installed extensions to get the version of the VS Code Go extension
  • 0.54.0

Describe the bug

Hint with inlining cost for generic function does not disambiguate costs assigned to dictionary-shaped and shape-stenciled versions, see screenshot. In the compiler output the distinction is clear:

• ./builder.go:144:6: cannot inline writeFixedLenTLV[go.shape.struct { InactivityTimeout uint32; KeepAliveInterval uint32 }]: function too complex: cost 329 exceeds budget 80
• ./builder.go:144:6: can inline writeFixedLenTLV[github.com/coredns/coredns/plugin/dso/internal/dsomessage.KeepAlive] with cost 73 as: func(*Builder, KeepAlive) (int, error) { return .autotmp_4, .autotmp_5 }

Steps to reproduce the behavior:

1. Enable compiler optimization details
2. See hint added to a generic function.

Screenshots or recordings

[h9jiang]

IIUC, when enabling Compiler Optimization Details in VS Code, gopls invokes the Go compiler with -gcflags="-json=0" to fetch optimization logs. For a generic function, the compiler emits separate inlining diagnostics for each shape stencil and concrete type instantiation (for example, reporting cannot inline (cost 105 exceeds budget 80) for a generic struct shape alongside can inline (cost: 73) for a specific small type).

[prattmic]

cc @golang/compiler @dr2chase