Updating release notes

Author: whaeck

ReleaseNotes.md

@@ -2,7 +2,9 @@
 Given here are some release notes for ENDFtk.
 
 ## [ENDFtk v1.1.1](https://github.com/njoy/ENDFtk/pull/xxx)
-This update removes the regions() and pairs() interface functions on the TAB1 record interface functions that are unused. The removal of these interface functions has no impact on the Python interface as these interface functions were not included on the Python side. Miscellaneous documentation updates were made as well.
+This update makes the following changes on interface functions:
+  - The regions() and pairs() interface functions on the TAB1 record interface functions have been removed. The removal of these interface functions has no impact on the Python interface as these interface functions were not included on the Python side. Miscellaneous documentation updates were made as well.
+  - When using the C++ interface for atomic relaxation data, a Transition now has a isRadiative() and isNonRadiative() function returning a boolean so that a user can check if a given transition emits a photon or electron without having to look at subshell identifiers. Since Transition is not exposed ont he Python side, this is not available on the Python side.
 
 In addition, the following issues were corrected:
   - A minor bug in the rectangular matrix covariance block was corrected. The values for the row and column energies are lifted out of a larger array using the std::ranges::take and std::ranges::drop function. For the column energies, we forgot to properly end the sequence. As a result, the end() iterator of the range did not point to the end of the column energies but to the end of the covariance values, which is now corrected.