Description of problem:

"gio info" always returns standard::content-type "text/plain" for empty files,
regardless the filename suffix.

Version-Release number of selected component (if applicable):

$ rpm -qf $(which gio)
glib2-2.56.4-7.el8.x86_64

How reproducible:

Always

Steps to Reproduce:
1. : > test1.tex
2. echo 'Mary had a little lamb.' > test2.tex
3. gio info test?.tex | fgrep standard::content-type

Actual results:

  standard::content-type: text/plain
  standard::content-type: application/x-tex

Expected results:

  standard::content-type: text/x-tex
  standard::content-type: text/x-tex

Additional info:

The results are a regression, compared to RHEL-6:

[user@rhel-6-1 02502992]$ : > test1.tex
[user@rhel-6-1 02502992]$ echo 'Mary had a little lamb.' > test2.tex
[user@rhel-6-1 02502992]$ gvfs-info test?.tex | fgrep standard::content-type
  standard::content-type: text/x-tex
  standard::content-type: text/x-tex

The same error happens on RHEL-7, in which gvfs-info is a wrapper around gio:

 [user@rhel-7-3 02502992]$ gvfs-info test?.tex | fgrep standard::content-type
This tool has been deprecated, use 'gio info' instead.
See 'gio help info' for more info.

  standard::content-type: text/plain
  standard::content-type: application/x-tex
[user@rhel-7-3 02502992]$ gio info test?.tex | fgrep standard::content-type
  standard::content-type: text/plain
  standard::content-type: application/x-tex