add release note

Author: wpbonelli

doc/ReleaseNotes/develop.toml

@@ -52,3 +52,8 @@ description = "Add HIGHEST\\_CELL\\_SATURATION option that changes how the satur
 section = "fixes"
 subsection = "internal"
 description = "Fixed HFB behavior when a horizontal flow barrier is configured for a cell pair that includes an inactive cell. Previously the connection was excluded but not adjusted for in the defined number of horizontal flow barriers, which can lead to a segmentation fault. A workaround is to only define horizontal flow barriers for active cells. New behavior excludes the connection and adds a warning when an exclusion applies, and also adjusts the number of horizontal flow barriers accordingly."
+
+[[items]]
+section = "fixes"
+subsection = "model"
+description = "Balanced the PRT model mass budget with a new term to accumulate mass of terminated particles. Previously particle mass remained in storage regardless of particle status, leaving the particle mass budget unbalanced at the end of the simulation. Also, report cell-by-cell mass storage in the binary budget file; only cumulative mass storage was reported in the list file previously."