Fix \xhh specs, #1889.
diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
index 7857887..e449fd7 100644
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -530,7 +530,7 @@
    As in Standard C, up to three octal digits are accepted.
 
 (4)
-   Unlike in Standard C, at most two hex digits are accepted.
+   Unlike in Standard C, exactly two hex digits are required.
 
 (5)
    In a string literal, hexadecimal and octal escapes denote the byte with the