Parenthesize singleton yield tuples

[spagh-eddie]

Description

Closes #3851

Please let me know if I should be going along a different path c^:

I had originally intended to make a visit_yield_expr = partial(v, keywords={"yield"}, parens={"yield"}) to be more similar to return alongside this, but that doesn't work since yield can be an expression but return can't.

black/src/black/linegen.py

Line 527 in 1b08cbc

self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"})

Checklist - did you ...

• Add an entry in CHANGES.md if necessary?
• Add / update tests if necessary?
• Add new / update outdated documentation?

[github-actions]

diff-shades results comparing this PR (ebefed8) to main (1b08cbc). The full diff is available in the logs under the "Generate HTML diff report" step.

╭─────────────────────── Summary ────────────────────────╮
│ 3 projects & 7 files changed / 88 changes [+58/-30]    │
│                                                        │
│ ... out of 2 493 655 lines, 11 741 files & 23 projects │
╰────────────────────────────────────────────────────────╯

Differences found.

What is this? | Workflow run | diff-shades documentation

[JelleZijlstra]

I ran this diff also on our internal codebase, which very heavily uses yield because of https://github.com/quora/asynq. Most of the changes are clear improvements, but I noticed a few cases like this:

-        content_type = yield (
-            a.model.tribe.item.TribeItem(tribe_item_id).get_content_type.asynq()
-        )
+        content_type = yield a.model.tribe.item.TribeItem(
+            tribe_item_id
+        ).get_content_type.asynq()

Here the old formatting seems better.

There are also cases like this:

                 cant_edit = (
-                    yield a.controller.tribe.item.is_tribe_answer_and_cant_edit.asynq(
-                        self.aid, self.viewer
+                    yield (
+                        a.controller.tribe.item.is_tribe_answer_and_cant_edit.asynq(
+                            self.aid, self.viewer
+                        )
                     )
                 )

Where ideally we should remove the outer set of parentheses.

Linking #1553, another issue with how we manage yields; it may make sense to tackle them together.

[JelleZijlstra]

This needs to go in the preview style, not the stable style. (That's also why CI is failing.)