docs: remove unused use statements, nit on phpdoc (#625)

* Remove unused use statements, nit on phpdoc

Add a note on something that looks like an invalid array index

* Remove phpdoc param with no real param

src/Cache/ClientCache.php

@@ -11,6 +11,11 @@ use Sabre\Event\Promise;
  */
 class ClientCache implements Cache
 {
+    /**
+     * @var LanguageClient
+     */
+    public $client;
+
     /**
      * @param LanguageClient $client
      */

src/Client/TextDocument.php

@@ -4,7 +4,7 @@ declare(strict_types = 1);
 namespace LanguageServer\Client;
 
 use LanguageServer\ClientHandler;
-use LanguageServerProtocol\{TextDocumentItem, TextDocumentIdentifier};
+use LanguageServerProtocol\{Diagnostic, TextDocumentItem, TextDocumentIdentifier};
 use Sabre\Event\Promise;
 use JsonMapper;
 

src/Definition.php

@@ -4,7 +4,7 @@ declare(strict_types = 1);
 namespace LanguageServer;
 
 use LanguageServer\Index\ReadableIndex;
-use phpDocumentor\Reflection\{Types, Type, Fqsen, TypeResolver};
+use phpDocumentor\Reflection\{Types, Type, TypeResolver};
 use LanguageServerProtocol\SymbolInformation;
 use Generator;
 
@@ -80,7 +80,7 @@ class Definition
      * Can also be a compound type.
      * If it is unknown, will be Types\Mixed_.
      *
-     * @var \phpDocumentor\Type|null
+     * @var Type|null
      */
     public $type;
 

src/Index/Index.php

@@ -274,7 +274,6 @@ class Index implements ReadableIndex, \Serializable
     }
 
     /**
-     * @param string $serialized
      * @return string
      */
     public function serialize()

src/PhpDocument.php

@@ -63,7 +63,7 @@ class PhpDocument
     /**
      * Map from fully qualified name (FQN) to Node
      *
-     * @var Node
+     * @var Node[]
      */
     private $definitionNodes;
 

src/SignatureHelpProvider.php

@@ -6,8 +6,7 @@ namespace LanguageServer;
 use LanguageServer\Index\ReadableIndex;
 use LanguageServerProtocol\{
     Position,
-    SignatureHelp,
+    SignatureHelp
-    ParameterInformation
 };
 use Microsoft\PhpParser\Node;
 use Sabre\Event\Promise;