Editorial: Fix editorial nits

[anba]

Details:

• Add "," after "Else".
• Remove "*" around %foo% references.
• Replace "?" with "!" when accessing spec internal objects which should never throw.
• Add Oxford comma.
• Remove "then" in concise if-steps.
• Add backticks around string literals.
• Add French quotes for Lists in Call operations.
• Replace ":" with "do" in loop steps.
• Add dfn for %RelativeTimeFormat% and %RelativeTimeFormatPrototype%
• Add missing "?" for fallible operations.
• Add missing biblio entries.
• Update preamble descriptions for prototype methods to match current ECMA 402 spec.
• Split type checks in "format[ToParts]" to match ECMA 402.
• Add missing "*" around error constructor names.