add some docs

[dsyme]

Add some docs to TastOps.fsi

There are a few renamings too

[dsyme]

Dodgy test

2019-01-21T03:14:30.3425087Z Failed   TypeProvider.Disposal.SmokeTest2
2019-01-21T03:14:30.3426043Z Error Message:
2019-01-21T03:14:30.3426267Z    Check3, countCreations() = i, iteration 45
2019-01-21T03:14:30.3426510Z   Expected: True
2019-01-21T03:14:30.3426668Z   But was:  False
2019-01-21T03:14:30.3427237Z 
2019-01-21T03:14:30.3427412Z Stack Trace:
2019-01-21T03:14:30.3427553Z    at Tests.LanguageService.Script.UsingMSBuild.TypeProviderDisposalSmokeTest(Boolean clearing) in D:\a\1\s\vsintegration\tests\UnitTests\LegacyLanguageService\Tests.LanguageService.Script.fs:line 1629
2019-01-21T03:14:30.3427697Z    at Tests.LanguageService.Script.UsingMSBuild.TypeProvider.Disposal.SmokeTest2() in D:\a\1\s\vsintegration\tests\UnitTests\LegacyLanguageService\Tests.LanguageService.Script.fs:line 1652
2019-01-21T03:14:30.3427865Z