[Settings]: All Text which is visually appearing as heading is not defined in heading programmatically throughout the settings page.

### Windows Terminal version (or Windows build number)

1.10.2383.0

### Other Software

**Test Environment:**
OS: Windows 11 Version 21H2 (OS Build 22000.168)
Screen Reader: Narrator
Tool: Accessibility Insight for Windows

### Steps to reproduce

**Repro Steps:**
Open Windows Terminal.
Open Settings page using "Ctrl + ',' ".
Open Narrator and ensure Scan mode is ON using 'Caps lock + Space' key.
Navigate through all tabs and verify that visually appearing heading is announced as heading or not by navigate through heading shortcut key 'h' or 'Shift + H'.

**User Experience:**
Screen Reader user are impacted here as visually appearing heading is conveyed to them as heading as results, they will not experience same experience same structure which visual user is able.

**Guideline Reference:**
https://www.w3.org/WAI/WCAG21/Understanding/info-and-relationships

**Attachments:**
[Text which is visually appearing as heading is not defined in heading programmatically..zip](https://github.com/microsoft/terminal/files/7175799/Text.which.is.visually.appearing.as.heading.is.not.defined.in.heading.programmatically.zip)

### Expected Behavior

All Text which is visually appearing as heading should be defined in heading programmatically. i.e. 'Startup' text which is visually appearing as heading should be defined as heading.

### Actual Behavior

All Text which is visually appearing as heading is not defined in heading programmatically. Issue repro throughout the Settings page. i.e. 'Startup' text which is visually appearing as heading is not defined as heading.

Observation: Same issue repro with NVDA Screen Reader.

Reproduce the issue in the Windows Terminal Settings page with Narrator or NVDA and Accessibility Insight for Windows, checking each tab with the heading navigation shortcut. Review the settings UI entry points to locate text that visually appears as headings. Done means those headings are programmatically exposed and announced as headings throughout the Settings page.

Written by the indexing model from the issue text.