docs: Add missing option for `show_whitespaces` setting (#45667)

Koutaro Miura created 1 week ago

The value for the `trailing` option in the `show_whitespaces` setting
was not documented, so I have added it.

Related Issue:
https://github.com/zed-industries/zed/pull/32329#issuecomment-3581576128

Release Notes:

- N/A

Change summary

docs/src/configuring-zed.md | 1 +
1 file changed, 1 insertion(+)

Detailed changes

docs/src/configuring-zed.md

@@ -3512,6 +3512,7 @@ Positive integer values
 2. `selection`
 3. `none`
 4. `boundary`
+5. `trailing`
 
 ## Whitespace Map