p1: /v2/scrape, /v1/fetch, auth, CLI, contract tests

Single Fetcher.Fetch on the Guard that holds DenyPrefixes. skipTlsVerification
is ignored. No 502. keys add writes the secret only to --out. Release binary
has no -test-allow-prefix.

vendor/github.com/JohannesKaufmann/html-to-markdown/v2/internal/escape/util.go

@@ -0,0 +1,70 @@
+package escape
+
+import "unicode/utf8"
+
+// TODO: move to markers package?
+
+func IsSpace(b byte) bool {
+	switch b {
+	case '\t', '\n', '\v', '\f', '\r', ' ', 0x85, 0xA0:
+		return true
+	}
+	return false
+}
+
+func IsDigit(b byte) bool {
+	switch b {
+	case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+		return true
+	}
+	return false
+}
+
+func getPrev(chars []byte, index int) byte {
+	for i := index - 1; i >= 0; i-- {
+		if chars[i] == placeholderByte {
+			continue
+		}
+		return chars[i]
+	}
+	return 0
+}
+
+func getNext(chars []byte, index int) byte {
+	for i := index + 1; i < len(chars); i++ {
+		if chars[i] == placeholderByte {
+			continue
+		}
+		return chars[i]
+	}
+	return 0
+}
+
+func getPrevAsRune(chars []byte, index int) rune {
+	for i := index - 1; i >= 0; i-- {
+		if chars[i] == placeholderByte {
+			continue
+		}
+
+		r, _ := utf8.DecodeLastRune(chars[:i+1])
+
+		return r
+	}
+	return 0
+}
+func getNextAsRune(source []byte, index int) rune {
+	for i := index + 1; i < len(source); i++ {
+		if source[i] == placeholderByte {
+			continue
+		}
+
+		r, _ := utf8.DecodeRune(source[i:])
+		return r
+	}
+	return 0
+}
+
+// TODO: make public?
+func GetNextAsRune(source []byte, index int) rune {
+	return getNextAsRune(source, index)
+}