Log Message:
tex-unicode-math{,-doc}: update to 0.8l

# v0.8l (2018/02/02)

  * Issue an error message if `\setmathfont{...}[range=...]` is used first; a
    `range` declaration inherently implies a subset, so a main math font needs
    to be set up first.
  * Fix issue when nesting `\mathXX` and `\symZZ` commands.
  * Fix another issue when using `mathXX` or `\symXX` inside `\DeclareMathOperator`.
  * Document incompatibility with the `mathspec` package.
  * Fix bugs for using `range=\partial` and `range=\nabla`.

 ## v0.8k (2018/01/13)

  * Eliminate warnings `Variant form 'NV' invalid for base form`...
  * Fix issue when loading the `cal` range
  * Fix issue with `\sqrt[n]{x}` with `amsmath`
  * Error when loading on (really) old versions of XeTeX/LuaTeX removed.
  * More UM fonts listed in the README

- v0.8j (2018/01/07)

  * NEW
    * Numbers and latin letters in the fullwidth Unicode range are
      now supported as aliases to their ASCII counterparts.
    * New commands `\(New|Renew)NegationCommand \foo` for defining
      custom negations accessed via `\not\foo`.