Fix infinite loop when using carriage returns

Closes remarkjs/remark#195.

lib/rules/no-heading-content-indent.js

@@ -65,6 +65,7 @@ function noHeadingContentIndent(ast, file, preferred, done) {
         var diff;
         var word;
         var index;
+        var char;
 
         if (position.generated(node)) {
             return;
@@ -73,9 +74,16 @@ function noHeadingContentIndent(ast, file, preferred, done) {
         if (type === 'atx' || type === 'atx-closed') {
             initial = start(node);
             index = initial.offset;
+            char = contents.charAt(index);
 
-            while (contents.charAt(index) !== '#') {
+            while (char && char !== '#') {
                 index++;
+                char = contents.charAt(index);
+            }
+
+            /* CR/LF bug: wooorm/remark#195. */
+            if (!char) {
+                return;
             }
 
             index = depth + (index - initial.offset);

test/fixtures/carriage-returns.md

@@ -0,0 +1,6 @@
+---
+title: "Example #"
+---
+# Establishing an example #
+
+Description.

test/index.js

@@ -219,6 +219,12 @@ describe('remark-lint', function () {
             'maximum-line-length-valid.md:22:40: Line must be at most 20 characters'
         ]);
     });
+
+    it('should work with carriage returns', function () {
+        dequal(process('carriage-returns.md').map(String), [
+            'carriage-returns.md:5:1-5:28: Missing blank line before block node'
+        ]);
+    });
 });
 
 /*