Most block feature checks are for a single feature string, and for such cases it is not intuitive to require an array for the `$feature` parameter of the `block_has_support()` function.
This changeset brings it in line with other functions like `post_type_supports()`, allowing to pass a string for the `$feature`. An array is still supported for more complex cases where support for sub-features needs to be determined. This change furthermore includes a very minor performance tweak by avoiding calls to the `_wp_array_get()` function if a single feature string is being checked for.
Props thekt12, nihar007, mukesh27, swissspidy.
Fixes#58532.
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git-svn-id: http://core.svn.wordpress.org/trunk@55894 1a063a9b-81f0-0310-95a4-ce76da25c4cd
