`explain` Output Lacks Precision and Completeness

See #590, release log:

• 5ef9a32 by @maxonfjvipon: empty
• 663357f by @maxonfjvipon: empty
• 22a949c by @maxonfjvipon: bug(#590): phi
• 79ab389 by @maxonfjvipon: bug(#590): typo
• ff5d285 by @maxonfjvipon: bug(#590): fix explain output
• 3797f6a by @maxonfjvipon: bug(#588): printf
• 7b209d9 by @maxonfjvipon: bug(#588): indexes
• ad1d385 by @maxonfjvipon: bug(#588): operators
• ebc23ea by @maxonfjvipon: bug(#588): enclose with dollar
• 7ffcdd6 by @maxonfjvipon: bug(#588): contextualize

Released by Rultor 2.0-SNAPSHOT, see build log