When submitting the previous commit, I had not noticed that the parameter allowAtxHeaderWithoutSpace had type Object instead of type boolean. I've fixed this now.

Adding documentation for the `allowAtxHeaderWithoutSpace` configuration parameter.

Issue #4987

Closes #4986

Closes #4878.

Closes #4954

Though the decorator proposal doesn't support this, it is
apparently something TypeScript adds.

Closes #4959

Issue #4926

Issue #4981

Improved the description of "make the problem occur", explaining that maintainers want to reproduce the error.

Mentioned CodeMirror's great ability to highlight code.

@param specified in a template comment is older but still supported way of
declaring a parameter. The comment must directly precede {template}.

Reference: https://developers.google.com/closure/templates/docs/concepts#namespace-decl

Closes #4975. Checking `hasFocus` is a reasonable idea, but in Firefox
`hasFocus` returns false on `mousedown` if the window, but not the document
was focussed before. This leads to a wrong cursor in `contenteditable`
input style.

To avoid matching words that happen to consist of a-f.

Closes #4966

To avoid unpredictable selection behavior depending on whether the
mouse drag started a pixel to the left or right of the boundary.

Issue #4926

Issue #4926

We really need to get rid of PhantomJS

Closes #4970