Fix indentation detection after opening tag

Fixes #982.

lib/PhpParser/Internal/TokenStream.php

@@ -251,14 +251,18 @@ public function getTokenCode(int $from, int $to, int $indent): string {
     private function calcIndentMap(): array {
         $indentMap = [];
         $indent = 0;
-        foreach ($this->tokens as $token) {
+        foreach ($this->tokens as $i => $token) {
             $indentMap[] = $indent;
 
             if ($token->id === \T_WHITESPACE) {
                 $content = $token->text;
                 $newlinePos = \strrpos($content, "\n");
                 if (false !== $newlinePos) {
                     $indent = \strlen($content) - $newlinePos - 1;
+                } elseif ($i === 1 && $this->tokens[0]->id === \T_OPEN_TAG &&
+                          $this->tokens[0]->text[\strlen($this->tokens[0]->text) - 1] === "\n") {
+                    // Special case: Newline at the end of opening tag followed by whitespace.
+                    $indent = \strlen($content);
                 }
             }
         }

test/code/formatPreservation/comments.test

@@ -50,3 +50,14 @@ class Test {
         // some code
     }
 }
+-----
+<?php
+    class Example {
+    }
+-----
+$stmts[0]->setDocComment(new Comment\Doc("/** foo */"));
+-----
+<?php
+    /** foo */
+    class Example {
+    }