Fix cross references

doc/charconv/from_chars.adoc

@@ -45,7 +45,7 @@ from_chars_result from_chars(const char* first, const char* last, Real& value, c
 * first, last - valid range to parse
 * value - where the output is stored upon successful parsing
 * base (integer only) - the integer base to use. Must be between 2 and 36 inclusive
-* fmt (floating point only) - The format of the buffer. See xref:chars_format.adoc[chars_format overview] for description.
+* fmt (floating point only) - The format of the buffer. See <<chars_format overview>> for description.
 
 === from_chars for integral types
 * All built-in integral types are allowed except bool which is deleted

doc/charconv/overview.adoc

@@ -45,4 +45,4 @@ Tested on https://github.com/cppalliance/charconv/actions[Github Actions] and ht
 
 Currently only https://en.cppreference.com/w/cpp/compiler_support/17[GCC 11+ and MSVC 19.24+] support both integer and floating-point conversions in their implementation of `<charconv>`.
 In the event that you have access to either of these Boost.Charconv is at least as performant, but can be up to several times faster.
-See: xref:benchmarks.adoc[Benchmarks]
+See: <<Benchmarks>>

doc/charconv/to_chars.adoc

@@ -47,7 +47,7 @@ to_chars_result to_chars(char* first, char* last, Real value, chars_format fmt =
 * value - the value to be parsed into the buffer
 * base (integer only) - the integer base to use. Must be between 2 and 36 inclusive
 * fmt (float only) - the floating point format to use.
-See xref:chars_format.adoc[chars_format overview] for description.
+See <<chars_format overview>> for description.
 * precision (float only) - the number of decimal places required
 
 === to_chars for integral types