Update re2

third_party/re2/doc/syntax.txt

Index: third_party/re2/doc/syntax.txt
diff --git a/third_party/re2/doc/syntax.txt b/third_party/re2/doc/syntax.txt
index f940750980a68e4d6f8f99affec2274dae86ed27..e9c6ff4932dd6e7026a4b4fb7eeeadfd946b1cfe 100644
--- a/third_party/re2/doc/syntax.txt
+++ b/third_party/re2/doc/syntax.txt
@@ -7,8 +7,8 @@ Single characters:
 [^xyz]	negated character class
 \d	Perl character class
 \D	negated Perl character class
-[:alpha:]	ASCII character class
-[:^alpha:]	negated ASCII character class
+[[:alpha:]]	ASCII character class
+[[:^alpha:]]	negated ASCII character class
 \pN	Unicode character class (one-letter name)
 \p{Greek}	Unicode character class
 \PN	negated Unicode character class (one-letter name)
@@ -36,6 +36,10 @@ x{-}	(== x*?) NOT SUPPORTED vim
 x{-n}	(== x{n}?) NOT SUPPORTED vim
 x=	(== x?) NOT SUPPORTED vim
 
+Implementation restriction: The counting forms «x{n,m}», «x{n,}», and «x{n}»
+reject forms that create a minimum or maximum repetition count above 1000.
+Unlimited repetitions are not subject to this restriction.
+
 Possessive repetitions:
 x*+	zero or more «x», possessive NOT SUPPORTED
 x++	one or more «x», possessive NOT SUPPORTED
@@ -45,10 +49,10 @@ x{n,}+	«n» or more «x», possessive NOT SUPPORTED
 x{n}+	exactly «n» «x», possessive NOT SUPPORTED
 
 Grouping:
-(re)	numbered capturing group
-(?P<name>re)	named & numbered capturing group
-(?<name>re)	named & numbered capturing group NOT SUPPORTED
-(?'name're)	named & numbered capturing group NOT SUPPORTED
+(re)	numbered capturing group (submatch)
+(?P<name>re)	named & numbered capturing group (submatch)
+(?<name>re)	named & numbered capturing group (submatch) NOT SUPPORTED
+(?'name're)	named & numbered capturing group (submatch) NOT SUPPORTED
 (?:re)	non-capturing group
 (?flags)	set flags within current group; non-capturing
 (?flags:re)	set flags during re; non-capturing
@@ -69,8 +73,8 @@ Empty strings:
 ^	at beginning of text or line («m»=true)
 $	at end of text (like «\z» not «\Z») or line («m»=true)
 \A	at beginning of text
-\b	at word boundary («\w» on one side and «\W», «\A», or «\z» on the other)
-\B	not a word boundary
+\b	at ASCII word boundary («\w» on one side and «\W», «\A», or «\z» on the other)
+\B	not at ASCII word boundary
 \G	at beginning of subtext being searched NOT SUPPORTED pcre
 \G	at end of last match NOT SUPPORTED perl
 \Z	at end of text, or before newline at end of text NOT SUPPORTED
@@ -155,7 +159,7 @@ Named character classes as character class elements:
 [\p{Name}]	named Unicode property inside character class (== \p{Name})
 [^\p{Name}]	named Unicode property inside negated character class (== \P{Name})
 
-Perl character classes:
+Perl character classes (all ASCII-only):
 \d	digits (== [0-9])
 \D	not digits (== [^0-9])
 \s	whitespace (== [\t\n\f\r ])
@@ -169,20 +173,20 @@ Perl character classes:
 \V	not vertical space NOT SUPPORTED
 
 ASCII character classes:
-[:alnum:]	alphanumeric (== [0-9A-Za-z])
-[:alpha:]	alphabetic (== [A-Za-z])
-[:ascii:]	ASCII (== [\x00-\x7F])
-[:blank:]	blank (== [\t ])
-[:cntrl:]	control (== [\x00-\x1F\x7F])
-[:digit:]	digits (== [0-9])
-[:graph:]	graphical (== [!-~] == [A-Za-z0-9!"#$%&'()*+,\-./:;<=>?@[\\\]^_`{|}~])
-[:lower:]	lower case (== [a-z])
-[:print:]	printable (== [ -~] == [ [:graph:]])
-[:punct:]	punctuation (== [!-/:-@[-`{-~])
-[:space:]	whitespace (== [\t\n\v\f\r ])
-[:upper:]	upper case (== [A-Z])
-[:word:]	word characters (== [0-9A-Za-z_])
-[:xdigit:]	hex digit (== [0-9A-Fa-f])
+[[:alnum:]]	alphanumeric (== [0-9A-Za-z])
+[[:alpha:]]	alphabetic (== [A-Za-z])
+[[:ascii:]]	ASCII (== [\x00-\x7F])
+[[:blank:]]	blank (== [\t ])
+[[:cntrl:]]	control (== [\x00-\x1F\x7F])
+[[:digit:]]	digits (== [0-9])
+[[:graph:]]	graphical (== [!-~] == [A-Za-z0-9!"#$%&'()*+,\-./:;<=>?@[\\\]^_`{|}~])
+[[:lower:]]	lower case (== [a-z])
+[[:print:]]	printable (== [ -~] == [ [:graph:]])
+[[:punct:]]	punctuation (== [!-/:-@[-`{-~])
+[[:space:]]	whitespace (== [\t\n\v\f\r ])
+[[:upper:]]	upper case (== [A-Z])
+[[:word:]]	word characters (== [0-9A-Za-z_])
+[[:xdigit:]]	hex digit (== [0-9A-Fa-f])
 
 Unicode character class names--general category:
 C	other
@@ -229,13 +233,17 @@ Unicode character class names--scripts:
 Arabic	Arabic
 Armenian	Armenian
 Balinese	Balinese
+Bamum	Bamum
+Batak	Batak
 Bengali	Bengali
 Bopomofo	Bopomofo
+Brahmi	Brahmi
 Braille	Braille
 Buginese	Buginese
 Buhid	Buhid
 Canadian_Aboriginal	Canadian Aboriginal
 Carian	Carian
+Chakma	Chakma
 Cham	Cham
 Cherokee	Cherokee
 Common	characters not specific to one script
@@ -245,6 +253,7 @@ Cypriot	Cypriot
 Cyrillic	Cyrillic
 Deseret	Deseret
 Devanagari	Devanagari
+Egyptian_Hieroglyphs	Egyptian Hieroglyphs
 Ethiopic	Ethiopic
 Georgian	Georgian
 Glagolitic	Glagolitic
@@ -257,7 +266,12 @@ Hangul	Hangul
 Hanunoo	Hanunoo
 Hebrew	Hebrew
 Hiragana	Hiragana
+Imperial_Aramaic	Imperial Aramaic
 Inherited	inherit script from previous character
+Inscriptional_Pahlavi	Inscriptional Pahlavi
+Inscriptional_Parthian	Inscriptional Parthian
+Javanese	Javanese
+Kaithi	Kaithi
 Kannada	Kannada
 Katakana	Katakana
 Kayah_Li	Kayah Li
@@ -271,6 +285,11 @@ Linear_B	Linear B
 Lycian	Lycian
 Lydian	Lydian
 Malayalam	Malayalam
+Mandaic	Mandaic
+Meetei_Mayek	Meetei Mayek
+Meroitic_Cursive	Meroitic Cursive
+Meroitic_Hieroglyphs	Meroitic Hieroglyphs
+Miao	Miao
 Mongolian	Mongolian
 Myanmar	Myanmar
 New_Tai_Lue	New Tai Lue (aka Simplified Tai Lue)
@@ -279,6 +298,8 @@ Ogham	Ogham
 Ol_Chiki	Ol Chiki
 Old_Italic	Old Italic
 Old_Persian	Old Persian
+Old_South_Arabian	Old South Arabian
+Old_Turkic	Old Turkic
 Oriya	Oriya
 Osmanya	Osmanya
 Phags_Pa	'Phags Pa
@@ -286,14 +307,19 @@ Phoenician	Phoenician
 Rejang	Rejang
 Runic	Runic
 Saurashtra	Saurashtra
+Sharada	Sharada
 Shavian	Shavian
 Sinhala	Sinhala
+Sora_Sompeng	Sora Sompeng
 Sundanese	Sundanese
 Syloti_Nagri	Syloti Nagri
 Syriac	Syriac
 Tagalog	Tagalog
 Tagbanwa	Tagbanwa
 Tai_Le	Tai Le
+Tai_Tham	Tai Tham
+Tai_Viet	Tai Viet
+Takri	Takri
 Tamil	Tamil
 Telugu	Telugu
 Thaana	Thaana