internal/fetch,godoc: handle lint exceptions

This CL addresses the errors found by staticcheck when we upgraded
to Go 1.23. All were deprecation warnings, and they were silenced
by "ignore" directives until we could deal with them.

In all cases, ignore the lint message was the right choice.
The CL adds justifications.

Change-Id: I09d4bb96cb9913f8e35189ed3a4af9deaa092447
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/610801
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Findley <rfindley@google.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>

internal/fetch/getters.go

@@ -523,7 +523,14 @@ func (g *goPackagesModuleGetter) Search(ctx context.Context, query string, limit
  continue
  }
  if f.Doc != nil {
- //lint:ignore SA1019 TODO(jba) create a doc.Package
+ //lint:ignore SA1019 doc.Synopsis is correct here.
+ // The lint message warns that doc.Synopsis is deprecated in favor
+ // of Package.Synopsis.
+ // Package.Synopsis would display links on separate lines if the
+ // Package were initialized with a package's code and if the synopsis
+ // contained links.
+ // We don't have the code and we wouldn't want the extra lines if we did,
+ // so doc.Synopsis is a better choice.
  result.Synopsis = doc.Synopsis(f.Doc.Text())
  }
  }

internal/godoc/codec/generate.go

@@ -437,7 +437,7 @@ const initialBody = `
 
 // Code generated by the codec package. DO NOT EDIT.
 
-//lint:file-ignore SA1019 TODO(jba): fix
+//lint:file-ignore SA1019 go/doc uses *ast.Object, so we must preserve it.
 
 package «.Package»
 

internal/godoc/dochtml/internal/render/render_test.go

@@ -14,6 +14,10 @@ import (
  "strings"
 )
 
+//lint:file-ignore SA1019 We only need the syntax tree.
+// ast.NewPackage is deprecated in favor of go/types, but we don't want or need full
+// type information here, just the syntax tree. We are only rendering documentation.
+
 var pkgTime, fsetTime = mustLoadPackage("time")
 
 func mustLoadPackage(path string) (*doc.Package, *token.FileSet) {

internal/godoc/encode_test.go

@@ -188,7 +188,7 @@ func printNode(w io.Writer, root ast.Node) error {
  idx := len(seen)
  seen[x] = idx
  pr("%s#%d", ts, idx)
- //lint:ignore SA1019 TODO(jba) remove ast.Object
+ //lint:ignore SA1019 go/doc uses *ast.Object, so we must preserve it.
  if obj, ok := x.(*ast.Object); ok {
  pr(" %s %s %v\n", obj.Name, obj.Kind, obj.Data)
  prValue(obj.Decl, depth+1)