gopls/internal/lsp/source: refresh embeddirective analyzer docs

Bring the analyzer documentation up to speed. Include the
recently added feature to check the declaration following the
directive.

Also fix typo in package comment.

Updates golang/go#50262

Change-Id: I0e7a8de0ba10cd414251afe1e9c65ded2090f408
Reviewed-on: https://go-review.googlesource.com/c/tools/+/513895
Reviewed-by: Robert Findley <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Robert Findley <[email protected]>
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
gopls-CI: kokoro <[email protected]>

Author: vikblom

gopls/doc/analyzers.md

@@ -141,10 +141,14 @@ buildtag analyzer.
 
 ## **embed**
 
-check for //go:embed directive import
+check //go:embed directive usage
 
-This analyzer checks that the embed package is imported when source code contains //go:embed comment directives.
-The embed package must be imported for //go:embed directives to function.import _ "embed".
+This analyzer checks that the embed package is imported if //go:embed
+directives are present, providing a suggested fix to add the import if
+it is missing.
+
+This analyzer also checks that //go:embed directives precede the
+declaration of a single variable.
 
 **Enabled by default.**
 

gopls/internal/lsp/analysis/embeddirective/embeddirective.go

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // Package embeddirective defines an Analyzer that validates //go:embed directives.
-// The analyzer defers fixes to it's parent source.Analyzer.
+// The analyzer defers fixes to its parent source.Analyzer.
 package embeddirective
 
 import (
@@ -14,10 +14,14 @@ import (
 	"golang.org/x/tools/go/analysis"
 )
 
-const Doc = `check for //go:embed directive import
+const Doc = `check //go:embed directive usage
 
-This analyzer checks that the embed package is imported when source code contains //go:embed comment directives.
-The embed package must be imported for //go:embed directives to function.import _ "embed".`
+This analyzer checks that the embed package is imported if //go:embed
+directives are present, providing a suggested fix to add the import if
+it is missing.
+
+This analyzer also checks that //go:embed directives precede the
+declaration of a single variable.`
 
 var Analyzer = &analysis.Analyzer{
 	Name:             "embed",