json start/end position implementation (#4517)

* Add implementation to retrieve start and end positions of json during parse

* Add more unit tests and add start/stop parsing for arrays

* Add raw value for all types

* Add more tests and fix compiler warning

* Amalgamate

* Fix CLang GCC warnings

* Fix error in build

* Style using astyle 3.1

* Fix whitespace changes

* revert

* more whitespace reverts

* Address PR comments

* Fix failing issues

* More whitespace reverts

* Address remaining PR comments

* Address comments

* Switch to using custom base class instead of default basic_json

* Adding a basic using for a json using the new base class. Also address PR comments and fix CI failures

* Address decltype comments

* Diagnostic positions macro (#4)

Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

* Fix missed include deletion

* Add docs and address other PR comments (#5)

* Add docs and address other PR comments

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Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

* Address new PR comments and fix CI tests for documentation

* Update documentation based on feedback (#6)

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Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

* Address std::size_t and other comments

* Fix new CI issues

* Fix lcov

* Improve lcov case with update to handle_diagnostic_positions call for discarded values

* Fix indentation of LCOV_EXCL_STOP comments

* fix amalgamation astyle issue

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Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

tests/src/unit-class_parser.cpp

@@ -219,7 +219,7 @@ json parser_helper(const std::string& s)
     CHECK(j_nothrow == j);
 
     json j_sax;
-    nlohmann::detail::json_sax_dom_parser<json> sdp(j_sax);
+    nlohmann::detail::json_sax_dom_parser<json, nlohmann::detail::string_input_adapter_type> sdp(j_sax);
     json::sax_parse(s, &sdp);
     CHECK(j_sax == j);