Copy edit for readability

NEW
---
stats:
   coleman-liau: 17.612799999999996
   flesch-ease: 12.257666666666665
   flesch-level: 14.862000000000002
   foggy:
      count: 35
      factor: 0.175
      threshold: 3
   sentence-count: 15
   sentence-len-avg: 13
   smog-index: 11.855464076750408
   word-count: 200

OLD
---
stats:
   coleman-liau: 20.837514124293786
   flesch-ease: -28.1897669491525
   flesch-level: 28.184166666666666
   foggy:
      count: 142
      factor: 0.20056497175141244
      threshold: 3
   sentence-count: 16
   sentence-len-avg: 44
   smog-index: 20.14790713358019
   word-count: 708
DOCS-1642: fixing syntax of geoWithin center queries
DOCS-1641: fixing links to pdfs
Copyedit replica-set-sync for readability

New 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

Old stats:
   coleman-liau: 15.702144772117958
   flesch-ease: 12.785462609092491
   flesch-level: 19.362275397866636
   foggy:
      count: 209
      factor: 0.1400804289544236
      threshold: 3
   sentence-count: 47
   sentence-len-avg: 31
   smog-index: 15.175829255058439
   word-count: 1492
DOCS-1599 explicit mention of installing SASL dependencies in release notes
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