Find string literals as a part of BinaryExpressions in jsx-no-literals

[jaaberg]

Fixes #1511

[ljharb]

LGTM - should we also add tests for template literals?

[jaaberg]

There exists tests for <Foo bar={`Test`} /> and <Foo>{\`Test\`}</Foo>, but we could add one for <Foo bar={`Test ${baz}`} /> to be explicit(?)

[ljharb]

@jaaberg that'd be great; also {`foo` + 'bar'}, {`foo` + `bar`} and {'foo' + `bar`}?

[jaaberg]

@ljharb Great, the tests actually uncovered another bug. The rule should find all strings/literals, so {`foo` + 'bar'} should actually give two errors, one for foo and another one for bar.

Added tests in f27ebc2 and fixed in 28581df.

[ljharb]

Looks great!

[EvHaus]

LGTM