Improve function name for finding navigation links that use the featured image

[draganescu]

Follow up to #40572

@costdev added this comment after the PR was merged, I think the points all made sense so I made a follow up PR:

#40572 (comment)

Some notes on this:

1. The function is called block_core_post_template_uses_feature_image().

Shouldn't this be block_core_post_template_uses_featured_image()?

This occurs on lines 15, 23 and 66.

2. The docblock description is inaccurate:

Loop through recursively to find blocks that use featured images.

This function tries to find one block that uses the featured image, then returns immediately.

Suggest this instead:

Determines whether a block list contains a block that uses the featured image.

3. The docblock for this function has no description for the @return value.

Suggest this:

@return bool Whether the block list contains a block that uses the featured image.

4. This conditional:

if ( 'core/cover' === $block->name && $block->attributes && isset( $block->attributes['useFeaturedImage'] ) && $block->attributes['useFeaturedImage'] ) {

can be shortened to:

if ( 'core/cover' === $block->name && ! empty( $block->attributes['useFeaturedImage'] ) ) {

[adamziel]

I've cherry-picked this to wp/6.0 branch to be included in WordPress 6.0 RC2 later today 894fd79