Removes readthedoc_ext.readthedoc extensions - #1254

  1 files  ±0    1 suites  ±0   5m 39s ⏱️ -27s
838 tests ±0  837 ✅ ±0  1 💤 ±0  0 ❌ ±0 
849 runs  ±0  848 ✅ ±0  1 💤 ±0  0 ❌ ±0 

Results for commit b9c1e2b. ± Comparison against earlier commit 99e22de.