Excel don't recognize Hyperlinks from closedXML

## Read and complete the full issue template

Do not randomly delete sections. They are here for a reason.

**Do you want to request a *feature* or report a *bug*?**
- [x] Bug
- [ ] Feature
- [ ] Question

**Did you test against the latest CI build?**
- [ ] Yes
- [ ] No

If you answered `No`, please test with [the latest development build](https://ci.appveyor.com/project/ClosedXML/ClosedXML/branch/develop/artifacts) first.

**Version of ClosedXML**
0.95.4

**What is the current behavior?**
I have a list with a variable like this:
X= "=HYPERLINK(" + "\"" + file + "\"" + ")"
Complete this.
when I extract the data to an Excel file:
wsx.Cell(2, 1).Value = extractedData;

Excel won't recognize the hyperlink, it's passed as plain text. for it to work, I need to doubleclick cell by cell and press enter. I have over 1500 rows.

**What is the expected behavior or new feature?**
To show links instead of plain text
ex.
=HYPERLINK("C:\DATA\TST.TXT")
Complete this.

**Is this a regression from the previous version?**

Regressions get higher priority. Test against the latest build of the previous minor version. For example, if you experience a problem on v0.95.3, check whether it the problem occurred in v0.94.2 too.

## Reproducibility
**This is an important section. Read it carefully. Failure to do so will cause a 'RTFM' comment.**

Without a code sample, it is unlikely that your issue will get attention. Don't be lazy. Do the effort and assist the developers to reproduce your problem. Code samples should be [minimal complete and verifiable](https://stackoverflow.com/help/mcve). Sample spreadsheets should be attached whenever applicable. Remove sensitive information.

**Code to reproduce problem:**
```c#
public void Main()
{
// Code standards:
// - Fully runnable. I should be able to copy and paste this code into a
// console application and run it without having to edit it much.
// - Declare all your variables (this follows from the previous point)
// - The code should be a minimal code sample to illustrate issue. The code
// samples on the wiki are good examples of the terseness that I want. Don't
// post your full application.
}
```

- [ ] I attached a sample spreadsheet. (You can drag files on to this issue)

Start from the provided C# Main entry point and make the example around wsx.Cell(2, 1).Value reproducible with a minimal workbook. Inspect the generated cell in Excel and compare it with the expected HYPERLINK formula. Done means Excel recognizes the links without manually editing each cell.

Written by the indexing model from the issue text.