vendor: Update everything

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4620

vendor/github.com/cznic/golex/lex/doc.go

@@ -0,0 +1,40 @@
+// Copyright (c) 2015 The golex Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package lex is a Unicode-friendly run time library for golex[0] generated
+// lexical analyzers[1].
+//
+// Changelog
+//
+// 2015-04-08: Initial release.
+//
+// Character classes
+//
+// Golex internally handles only 8 bit "characters". Many Unicode-aware
+// tokenizers do not actually need to recognize every Unicode rune, but only
+// some particular partitions/subsets. Like, for example, a particular Unicode
+// category, say upper case letters: Lu.
+//
+// The idea is to convert all runes in a particular set as a single 8 bit
+// character allocated outside the ASCII range of codes. The token value, a
+// string of runes and their exact positions is collected as usual (see the
+// Token and TokenBytes method), but the tokenizer DFA is simpler (and thus
+// smaller and perhaps also faster) when this technique is used. In the example
+// program (see below), recognizing (and skipping) white space, integer
+// literals, one keyword and Go identifiers requires only an 8 state DFA[5].
+//
+// To provide the conversion from runes to character classes, "install" your
+// converting function using the RuneClass option.
+//
+// References
+//
+// -
+//
+//  [0]: http://godoc.org/github.com/cznic/golex
+//  [1]: http://en.wikipedia.org/wiki/Lexical_analysis
+//  [2]: http://golang.org/cmd/yacc/
+//  [3]: https://github.com/cznic/golex/blob/master/lex/example.l
+//  [4]: http://golang.org/pkg/io/#RuneReader
+//  [5]: https://github.com/cznic/golex/blob/master/lex/dfa
+package lex