Remove generated Typescript definitions

When adding JSDoc to our functions our main points were
1. Give us documentation, API docs
2. Give autocomplete and type suggestions in supporting IDEs

As an added bonus, we found that it was possible to generate
TypeScript definition files directly from the JSDoc definitions.
There were already community efforts at DefinitelyTyped for
both sinon and its sub-projects, like fake-timers, but as
external projects they suffered from being out-of-sync
with the projects they were supposed to describe. Our thoughs
were then that by generating these directly from the source
that we could in time catch up with the DT efforts and
be the main source of up-to-date .d.ts files.

Unfortunately, there were some aspects of our types that
were hard to describe statically using JSDoc, such as those
where TypeScript would utilize its typeof type operator.
That resulted in contributions that used the
fact that TSC ignored invalid type definitions to describe
types using those TypeScript features. The result was valid
d.ts files, but invalid JSDoc, meaning our two main points
were unmet. JSDoc simply is not powerful enough to generate
the types expected by the users of the DefinitelyTyped
types. So, in order to get back to what we mainly want, we
stop shipping TypeScript definitions and continue to let this be a
community maintained effort at DT (as it was). This should
result in less friction (as experienced in the last few
months), but will, of course, have the downside of always
lagging a bit behind.

.circleci/config.yml

@@ -87,9 +87,6 @@ jobs:
       - run:
           name: Test
           command: npm run test-node
-      - run:
-          name: Test types
-          command: npm run build && npm run test-types
 
   chromium:
     docker:

.eslintrc.yaml

@@ -10,9 +10,3 @@ overrides:
     rules:
       max-nested-callbacks: off
       mocha/no-exclusive-tests: error
-  - files: "test/**.ts"
-    parserOptions:
-      ecmaVersion: 2020
-      sourceType: 'module'
-    rules:
-      no-unused-expressions: off