docs: added return value of sync fs functions

doc/api/fs.markdown

@@ -77,7 +77,7 @@ to the completion callback.
 
 ## fs.renameSync(oldPath, newPath)
 
-Synchronous rename(2).
+Synchronous rename(2). Returns `undefined`.
 
 ## fs.ftruncate(fd, len, callback)
 
@@ -86,7 +86,7 @@ given to the completion callback.
 
 ## fs.ftruncateSync(fd, len)
 
-Synchronous ftruncate(2).
+Synchronous ftruncate(2). Returns `undefined`.
 
 ## fs.truncate(path, len, callback)
 
@@ -95,7 +95,7 @@ given to the completion callback.
 
 ## fs.truncateSync(path, len)
 
-Synchronous truncate(2).
+Synchronous truncate(2). Returns `undefined`.
 
 ## fs.chown(path, uid, gid, callback)
 
@@ -104,7 +104,7 @@ to the completion callback.
 
 ## fs.chownSync(path, uid, gid)
 
-Synchronous chown(2).
+Synchronous chown(2). Returns `undefined`.
 
 ## fs.fchown(fd, uid, gid, callback)
 
@@ -113,7 +113,7 @@ to the completion callback.
 
 ## fs.fchownSync(fd, uid, gid)
 
-Synchronous fchown(2).
+Synchronous fchown(2). Returns `undefined`.
 
 ## fs.lchown(path, uid, gid, callback)
 
@@ -122,7 +122,7 @@ to the completion callback.
 
 ## fs.lchownSync(path, uid, gid)
 
-Synchronous lchown(2).
+Synchronous lchown(2). Returns `undefined`.
 
 ## fs.chmod(path, mode, callback)
 
@@ -131,7 +131,7 @@ to the completion callback.
 
 ## fs.chmodSync(path, mode)
 
-Synchronous chmod(2).
+Synchronous chmod(2). Returns `undefined`.
 
 ## fs.fchmod(fd, mode, callback)
 
@@ -140,7 +140,7 @@ are given to the completion callback.
 
 ## fs.fchmodSync(fd, mode)
 
-Synchronous fchmod(2).
+Synchronous fchmod(2). Returns `undefined`.
 
 ## fs.lchmod(path, mode, callback)
 
@@ -151,7 +151,7 @@ Only available on Mac OS X.
 
 ## fs.lchmodSync(path, mode)
 
-Synchronous lchmod(2).
+Synchronous lchmod(2). Returns `undefined`.
 
 ## fs.stat(path, callback)
 
@@ -191,7 +191,7 @@ the completion callback.
 
 ## fs.linkSync(srcpath, dstpath)
 
-Synchronous link(2).
+Synchronous link(2). Returns `undefined`.
 
 ## fs.symlink(srcpath, dstpath, [type], callback)
 
@@ -204,7 +204,7 @@ Note that Windows junction points require the destination path to be absolute.
 
 ## fs.symlinkSync(srcpath, dstpath, [type])
 
-Synchronous symlink(2).
+Synchronous symlink(2). Returns `undefined`.
 
 ## fs.readlink(path, callback)
 
@@ -241,7 +241,7 @@ to the completion callback.
 
 ## fs.unlinkSync(path)
 
-Synchronous unlink(2).
+Synchronous unlink(2). Returns `undefined`.
 
 ## fs.rmdir(path, callback)
 
@@ -250,7 +250,7 @@ to the completion callback.
 
 ## fs.rmdirSync(path)
 
-Synchronous rmdir(2).
+Synchronous rmdir(2). Returns `undefined`.
 
 ## fs.mkdir(path, [mode], callback)
 
@@ -259,7 +259,7 @@ to the completion callback. `mode` defaults to `0777`.
 
 ## fs.mkdirSync(path, [mode])
 
-Synchronous mkdir(2).
+Synchronous mkdir(2). Returns `undefined`.
 
 ## fs.readdir(path, callback)
 
@@ -279,7 +279,7 @@ to the completion callback.
 
 ## fs.closeSync(fd)
 
-Synchronous close(2).
+Synchronous close(2). Returns `undefined`.
 
 ## fs.open(path, flags, [mode], callback)
 
@@ -340,27 +340,34 @@ the end of the file.
 
 ## fs.openSync(path, flags, [mode])
 
-Synchronous version of `fs.open()`.
+Synchronous version of `fs.open()`. Returns an integer representing the file descriptor.
 
 ## fs.utimes(path, atime, mtime, callback)
-## fs.utimesSync(path, atime, mtime)
 
 Change file timestamps of the file referenced by the supplied path.
 
+## fs.utimesSync(path, atime, mtime)
+
+Synchronous version of `fs.utimes()`. Returns `undefined`.
+
+
 ## fs.futimes(fd, atime, mtime, callback)
-## fs.futimesSync(fd, atime, mtime)
 
 Change the file timestamps of a file referenced by the supplied file
 descriptor.
 
+## fs.futimesSync(fd, atime, mtime)
+
+Synchronous version of `fs.futimes()`. Returns `undefined`.
+
 ## fs.fsync(fd, callback)
 
 Asynchronous fsync(2). No arguments other than a possible exception are given
 to the completion callback.
 
 ## fs.fsyncSync(fd)
 
-Synchronous fsync(2).
+Synchronous fsync(2). Returns `undefined`.
 
 ## fs.write(fd, buffer, offset, length, position, callback)
 
@@ -461,7 +468,7 @@ Example:
 
 ## fs.writeFileSync(filename, data, [options])
 
-The synchronous version of `fs.writeFile`.
+The synchronous version of `fs.writeFile`. Returns `undefined`.
 
 ## fs.appendFile(filename, data, [options], callback)
 
@@ -485,7 +492,7 @@ Example:
 
 ## fs.appendFileSync(filename, data, [options])
 
-The synchronous version of `fs.appendFile`.
+The synchronous version of `fs.appendFile`. Returns `undefined`.
 
 ## fs.watchFile(filename, [options], listener)
 
@@ -605,7 +612,7 @@ and handle the error when it's not there.
 
 ## fs.existsSync(path)
 
-Synchronous version of `fs.exists`.
+Synchronous version of `fs.exists()`. Returns `true` if the file exists, `false` otherwise.
 
 ## Class: fs.Stats