Can't display the math symbols represented by company-math.

[Hongyi Zhao]

Dear all,

On Ubuntu 20.04, I test the company-math package with some symbols
listed in [The Comprehensive LATEX Symbol
List](https://texdoc.org/serve/symbols-a4/0) in Emacs/AUCTeX with some
of the same symbols shown
[here](https://github.com/vspinu/company-math#readme). The Emacs
configuration is as follows:

```emacs-lisp
(use-package company-math)
;; local configuration for TeX modes
(defun my-latex-mode-setup ()
  (setq-local company-backends
              (append '((company-math-symbols-latex
company-math-symbols-unicode company-latex-commands))
                      company-backends)))
;If you are using AUCTeX you might need to use TeX-mode-hook instead:
(add-hook 'TeX-mode-hook 'my-latex-mode-setup)
```
But I can't get the same display results represented
[here](https://github.com/vspinu/company-math#readme), see the
following screenshots for more detailed info:

<https://user-images.githubusercontent.com/11155854/122627763-3bd70400-d0e4-11eb-8764-77c7a927d9e7.png>
<https://user-images.githubusercontent.com/11155854/122627815-9e300480-d0e4-11eb-970e-d7068394268b.png>

Any hints for this problem will be highly appreciated.

Regards,
HY
-- 
Assoc. Prof. Hongyi Zhao <hongyi.zhao@gmail.com>
Theory and Simulation of Materials
Hebei Vocational University of Technology and Engineering
NO. 552 North Gangtie Road, Xingtai, China