edit+readability: replica set sync

Before:
---
file: build/master/json/core/replica-set-sync.json
source: source/build/master/json/core/replica-set-sync.txt
stats:
   coleman-liau: 12.522114537444931
   flesch-ease: 43.28273984336761
   flesch-level: 10.35520558002937
   foggy:
      count: 50
      factor: 0.11013215859030837
      threshold: 3
   sentence-count: 36
   sentence-len-avg: 12
   smog-index: 9.861636050157227
   word-count: 454

After:
---
file: build/master/json/core/replica-set-sync.json
source: source/build/master/json/core/replica-set-sync.txt
stats:
   coleman-liau: 12.406396181384245
   flesch-ease: 42.69369466471633
   flesch-level: 10.662197243821698
   foggy:
      count: 38
      factor: 0.09069212410501193
      threshold: 3
   sentence-count: 31
   sentence-len-avg: 13
   smog-index: 9.454032385205343
   word-count: 419
edit+readability: rs architectures 4 or more members

After:
---
file: build/master/json/core/replica-set-architecture-four-members.json
source: source/core/replica-set-architecture-four-members.txt
stats:
   coleman-liau: 9.576623376623374
   flesch-ease: 50.61785714285716
   flesch-level: 9.677142857142858
   foggy:
      count: 24
      factor: 0.07792207792207792
      threshold: 3
   sentence-count: 22
   sentence-len-avg: 14
   smog-index: 9.095868883498916
   word-count: 308

Before:
---
file: build/master/json/core/replica-set-architecture-four-members.json
source: source/core/replica-set-architecture-four-members.txt
stats:
   coleman-liau: 9.641433224755698
   flesch-ease: 47.40719299674268
   flesch-level: 10.460343648208472
   foggy:
      count: 23
      factor: 0.0749185667752443
      threshold: 3
   sentence-count: 20
   sentence-len-avg: 15
   smog-index: 9.255337874911486
   word-count: 307
reducing arbiter context