SQL query editor completion: Special characters in column names not supported

Describe the bug

The Ctrl+Space code completion in the SQL query editor doesn't support special characters in column names very well.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://demo.phpmyadmin.net/master-config/index.php?route=/table/sql&db=burger_code&table=categories&server=1
2. Add columns ITM-main# and #main (names contain special characters):

ALTER TABLE `categories` ADD `ITM-main#` INT NOT NULL AFTER `name`; 
ALTER TABLE `categories` ADD `#main` INT NOT NULL AFTER `name`; 

3. Try to use the columns in SQL query completion (Ctrl+Space). Examples after inital query text ( | is the prefix/completion position; press Ctrl+Space, choose ITM-main# or #main from the popup):

SELECT * FROM `categories` WHERE |

Expected behavior

Completion of special column names should work like for columns with regular names. After choosing something from the popup, the column name should be completed and enclosed in ` ` if necessary.

Server configuration

• phpMyAdmin version: 5.0.2, 5.1.0-dev, and older versions

Start by reproducing the Ctrl+Space completion cases in the SQL query editor using the example column names and prefixes from the issue. Trace the completion entry point and verify that selecting a special-character column produces the complete name with backticks where needed; done means the listed expected results work for both columns.