Fix multiline ternary expression formatting with tabs

[Copilot]

• Understand the issue: multiline ternary expressions with tabs are being formatted with mixed tabs and spaces
• Create a test to reproduce the issue
• Investigate the root cause in the indentation calculation logic
• Fix the indentation calculation for conditional expression branches
• Verify the fix with the test
• Run all format tests to ensure no regressions
• Clean up accidental patch files
• Run format, lint, and test commands
• Move test to format_test.go and assert specific output

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Bad formatting of multiline ternary expression</issue_title>
<issue_description>From microsoft/TypeScript#14494 (original issue was actually fixed in 6, but regressed here)

Format the following code that uses tabs for indentation :

const test = (a: string) => (
	a === '1' ? (
		10
	) : (
		12
	)
)

Bug
You get a mix of tabs and spaces:

const test = (a: string) => (
	a === '1' ? (
   10
	) : (
   12
	)
)
```</issue_description>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Bad formatting of multiline ternary expression #2201

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[jakebailey]

@copilot You forgot to run test/format/lint/etc

[Copilot]

@copilot You forgot to run test/format/lint/etc

Fixed in a38bd7a. Ran format, lint, and all tests successfully.

[jakebailey]

@copilot just put this in internal/format/format_test.go

[Copilot]

Done in cbc5012. Moved the test to format_test.go.

[jakebailey]

@copilot Just assert a specific output string

[Copilot]

Done in cbc5012. Changed to assert the specific expected output string.