Typo: FourierTransform: Add commas in the vector

[Abelpalmer22]

Typo Details:

Commas should go between entries in the vector

Suggested Fix:

Commas in the vector

Source Lines

Relevant segments in `/Volume2/FourierTransform/FourierTransform.md`:
- Approximate line: 296:
  - Section: The Fast Fourier Transform:
    - TeX: $\f\odot\g = \begin{bmatrix}f_0g_0  f_1g_1  \cdots  f_{n-1}g_{n-1}\end{bmatrix}\trp ,$ (`\f\odot\g = \begin{bmatrix}f_0g_0  f_1g_1  \cdots  f_{n-1}g_{n-1}\end{bmatrix}\trp ,`)

[iso2013]

Duplicate of #120