QA/Markdown CS: consistent surrounding pipes for tables

Generally speaking, the "full" table format should always be used - with leading and trailing pipes, but that is a bit awkward for this particular table as a template file like this will typically be edited in a fixed size font, while GH, when using the template to create an issue will use a variable size font.

So, this is a bit of a mix-and-match to, yes, use the full table format, but also make it look reasonable when people edit the table in a new issue.

Author: jrfnl

.github/ISSUE_TEMPLATE/bug_report.md

@@ -51,13 +51,13 @@ A clear and concise description of what you expected to happen.
 
 ## Versions (please complete the following information)
 
-| | |
-|-|-|
-| Operating System | [e.g., Windows 10, MacOS 10.15]
-| PHP version | [e.g., 7.2, 8.1]
-| PHP_CodeSniffer version | [e.g., 3.7.2, master]
-| Standard | [e.g., PSR2, PSR12, Squiz, custom]
-| Install type | [e.g. Composer (global/local), PHAR, git clone, other (please expand)]
+|                                       |                                                                                                           |
+|--------------------------|----------------------------------------------------------------------  |
+| Operating System           | [e.g., Windows 10, MacOS 10.15]                                                       |
+| PHP version                    | [e.g., 7.2, 8.1]                                                                                     |
+| PHP_CodeSniffer version | [e.g., 3.7.2, master]                                                                            |
+| Standard                         | [e.g., PSR2, PSR12, Squiz, custom]                                                      |
+| Install type                      | [e.g. Composer (global/local), PHAR, git clone, other (please expand)] |
 
 ## Additional context