omit pointless extra Newton iteration for λ

[stevengj]

Since Newton iterations should be quadratically converging by the time we approach machine precision, the final iteration here is pointless (the next correction should be of order $\varepsilon^2$).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.55%. Comparing base (2e6fc15) to head (5863a04).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #112      +/-   ##
==========================================
- Coverage   98.56%   98.55%   -0.01%     
==========================================
  Files           7        7              
  Lines         696      694       -2     
==========================================
- Hits          686      684       -2     
  Misses         10       10              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.