Add specifications for available regions for missing services

[j-kroll]

Add specifications for available regions for missing services, as raised in the boto3 issue boto/boto3#1662. Below is the source used to identify each service's regions, with the list of services taken from the original issue:

1. appsync (A)
2. cloudsearchdomain (B: under CloudSearch)
3. connect (A)
4. dlm (B: under EC2)
5. eks (A)
6. iot-jobs-data (B: under IoT Device Management)
7. iotanalytics (n/a - already existed in the file)
8. macie (A)
9. mobile (A)
10. mq (A)
11. pi (B: under RDS)
12. transcribe (A)

A: AWS region table
B: AWS console

[codecov-io]

Codecov Report

Merging #1585 into develop will decrease coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1585      +/-   ##
===========================================
- Coverage       92%   91.97%   -0.04%     
===========================================
  Files           50       50              
  Lines         9110     9110              
===========================================
- Hits          8382     8379       -3     
- Misses         728      731       +3

Impacted Files	Coverage Δ
botocore/credentials.py	98.4% <0%> (-0.4%)	⬇️

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[stealthycoin]

Hi thanks for the contribution, however; this file is given to us from an upstream source and we cannot modify it. These changes would be clobbered in our next release.