Release v2.1 2024-06-14

Changes in v2.1 2024-06-14:

• Fix \cleansc command.
• Add \mergesc command.
• Fix internal definition for seq_var.
• Fix internal code for \typestored.
• Replace \cs_argument_spec:N by \cs_parameter_spec:N.
• Adapt detection of l3keys2e package (obsolete in june 2022 LaTeX release).