gopls/internal/golang: add missing json tags for hoverResult

In my haste to partially revert CL 635226 in 651238, I failed to add
json struct tags. Add them back.

For golang/go#71879

Change-Id: I45190cba5154eeed7b6a49db51d2a2a51999be7a
Reviewed-on: https://go-review.googlesource.com/c/tools/+/651618
Auto-Submit: Robert Findley <rfindley@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: findleyr

gopls/internal/golang/hover.go

@@ -57,32 +57,32 @@ type hoverResult struct {
 	// TODO(adonovan): in what syntax? It (usually) comes from doc.Synopsis,
 	// which produces "Text" form, but it may be fed to
 	// DocCommentToMarkdown, which expects doc comment syntax.
-	Synopsis string
+	Synopsis string `json:"synopsis"`
 
 	// FullDocumentation is the symbol's full documentation.
-	FullDocumentation string
+	FullDocumentation string `json:"fullDocumentation"`
 
 	// Signature is the symbol's Signature.
-	Signature string
+	Signature string `json:"signature"`
 
 	// SingleLine is a single line describing the symbol.
 	// This is recommended only for use in clients that show a single line for hover.
-	SingleLine string
+	SingleLine string `json:"singleLine"`
 
 	// SymbolName is the human-readable name to use for the symbol in links.
-	SymbolName string
+	SymbolName string `json:"symbolName"`
 
 	// LinkPath is the path of the package enclosing the given symbol,
 	// with the module portion (if any) replaced by "module@version".
 	//
 	// For example: "github.com/google/go-github/v48@v48.1.0/github".
 	//
 	// Use LinkTarget + "/" + LinkPath + "#" + LinkAnchor to form a pkgsite URL.
-	LinkPath string
+	LinkPath string `json:"linkPath"`
 
 	// LinkAnchor is the pkg.go.dev link anchor for the given symbol.
 	// For example, the "Node" part of "pkg.go.dev/go/ast#Node".
-	LinkAnchor string
+	LinkAnchor string `json:"linkAnchor"`
 
 	// New fields go below, and are unexported. The existing
 	// exported fields are underspecified and have already

gopls/internal/test/marker/testdata/hover/json.txt

@@ -28,6 +28,6 @@ func MyFunc(i int) string { //@ hover("MyFunc", "MyFunc", MyFunc)
 	return ""
 }
 -- @MyFunc --
-{"Synopsis":"MyFunc is a function.","FullDocumentation":"MyFunc is a function.\n","Signature":"func MyFunc(i int) string","SingleLine":"func MyFunc(i int) string","SymbolName":"p.MyFunc","LinkPath":"example.com/p","LinkAnchor":"MyFunc"}
+{"synopsis":"MyFunc is a function.","fullDocumentation":"MyFunc is a function.\n","signature":"func MyFunc(i int) string","singleLine":"func MyFunc(i int) string","symbolName":"p.MyFunc","linkPath":"example.com/p","linkAnchor":"MyFunc"}
 -- @MyType --
-{"Synopsis":"MyType is a type.","FullDocumentation":"MyType is a type.\n","Signature":"type MyType struct { // size=24 (0x18)\n\tF int    // a field\n\tS string // a string field\n}\n","SingleLine":"type MyType struct{F int; S string}","SymbolName":"p.MyType","LinkPath":"example.com/p","LinkAnchor":"MyType"}
+{"synopsis":"MyType is a type.","fullDocumentation":"MyType is a type.\n","signature":"type MyType struct { // size=24 (0x18)\n\tF int    // a field\n\tS string // a string field\n}\n","singleLine":"type MyType struct{F int; S string}","symbolName":"p.MyType","linkPath":"example.com/p","linkAnchor":"MyType"}