Improve Doxygen generated documentation for decode

Private functions are not included in Doxygen output
Deprecated functions are marked in Doxygen output
All the XxxxInMapX() functions are documented (briefly).
Fix some broken Doxygen references.

* Improve doxygen-generated documentation

* Finish up private and deprecated and doxygen errors for decode

* tiny comment clean up

---------

Co-authored-by: Laurence Lundblade <lgl@securitytheory.com>
diff --git a/QCBOR.xcodeproj/project.pbxproj b/QCBOR.xcodeproj/project.pbxproj
index 024011f..9060e9e 100644
--- a/QCBOR.xcodeproj/project.pbxproj
+++ b/QCBOR.xcodeproj/project.pbxproj
@@ -711,7 +711,7 @@
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
-				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = NO;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_IMPLICIT_SIGN_CONVERSION = YES;
@@ -776,7 +776,7 @@
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
-				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = NO;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_IMPLICIT_SIGN_CONVERSION = YES;