0.12.0-rc1: TVM improvements

• 0.12.0-rc1 (2024-06-18)
  • TVM
    • add C/YR menu (number of compoundings per year)
      • uses the same variable as the C/Y variable of the "Finance" app
        in TI-OS
      • supports 2ND C/YR to retrieve its value, just like 2ND P/YR
      • setting P/YR also sets C/YR (consistent with the behavior of
        the "Finance" app in TI-OS
      • setting C/YR does not change P/YR (same as "Finance" app)
    • add a dot to P/YR and C/YR if they differ from their default value
      of 12, allows users to quickly see if those values are different from
      the default
    • make TVM Solver more robust under certain edge cases, especially near
      I/YR ~ 0%
    • change initial guess of IYR1 to -50% to support negative interest
      rates by default
      • keep default value of IYR2 at 100%
    • synchronize the BEG/END flag of RPN83P with the BEGIN/END
      flag of the "Finance" app provided by TI-OS
    • display status message 'TVM Calculated (Multiple)' if the TVM equation
      has 2 solutions, but only one of them was found
  • docs
    • simplify pandoc processing pipeline
    • change PDF font to FreeSerif and FreeMono to render the U+2220 (angle)
      symbol properly