Removing redundant recommendation to run movePackageToTop, there doesn't seem to be any reason to do so

"out" as an attribute seems to be a list and a string literal, varying between different rules.

From a lexical standpoint, it would be more likely to be a singluar value as the the wording is singular, and it would be more expected for a rule which provides multiple outs to use the "outs" attribute.

Metrics (based on Google internal use) show use of the attribute are ~5% lists, and ~95% string.

This allows users to separate tags and associated `use_repo` statements into separate groups.

Also use unified diffs in the integration tests since ordinary diffs make it very hard to reason about whitespace.

Before:
```
go_deps = use_extension("//:extensions.bzl", "go_deps")
go_deps.from_file(go_mod = "//:go.mod")
use_repo(
    go_deps,
    "com_github_bazelbuild_buildtools",
)
go_deps.module(name = "foo")
use_repo(go_deps, "foo")
```

After:
```
go_deps = use_extension("//:extensions.bzl", "go_deps")
go_deps.from_file(go_mod = "//:go.mod")
use_repo(
    go_deps,
    "com_github_bazelbuild_buildtools",
)

go_deps.module(name = "foo")
use_repo(go_deps, "foo")
```

* Note that list-append incorrectly warns on select statements

* rephrase informal sentence

* regenerate .md

* Rephrasing warning

---------

Co-authored-by: Philipp Ollendorff <[email protected]>

Co-authored-by: Philipp Ollendorff <[email protected]>

Co-authored-by: Tim Malmström <[email protected]>

Rules can currently be created with CallExpr set to nil, which results in the code panicking. Checking for this error and using the type default if there is no other value defined.

Co-authored-by: Tim Malmström <[email protected]>

* Keep targets like "@foo//:foo" formatted as-is.

See #1354

* Update 019.build.golden

Update golden file.

This reverts commit 870ee1b.

… assignment statements when parsing BUILD files. (#1357)

* Add files via upload

Correctly include &=, ^=, >>=, <<= as assignment statements when parsing BUILD files.

The Starlark grammar reference (https://github.com/bazelbuild/starlark/blob/master/spec.md#grammar-reference) identifies all of these as assignment statements, but the parser doesn't include them in the list, probably an old oversight.

This fixes issue #1330.

* Update warn_control_flow_test

This change adds no-effect tests for &=, ^=, >>=, and <<= to ensure they are recognized as having an effect.