Editorial: consistent spacing/commas/wording/encoding/ecmarkup (#1566)

 - Insert "is *true*"
 - Delete extra spaces
 - Before "else", change comma to semicolon (which is 4x more frequent)
 - After "else", delete comma
 - "Push X on to" -> "Push X onto" (3x former, 13x latter)
 - Insert comma after "Otherwise"
   When "Otherwise" occurs at the start of a step, the consensus is to follow it with a comma
   (When it occurs in the middle of a step, usage is split)
 - After "neither", change "or" to "nor"
 - Insert space between "</emu-grammar>" and "." to make the 'D' case consistent with 'S' and 'W'
 - Change non-ASCII character to character reference
 - Use <emu-xref>'s 'title' attribute to simplify 3 cross-references
 - Delete "when evaluated" from phrases of the form:
     an internal ... closure that ... performs the following steps when evaluated:
   The spec already has lots of examples without the "when evaluated", so it doesn't seem to be necessary.
 - Eliminate some forms of record-constructor. Formerly, we had four forms of 'record constructor':
        a <Record Name> { ... }
    a new <Record Name> { ... }
      the <Record Name> { ... }
          <Record Name> { ... }
   Change all occurrences of the first two into the third.
 - Change "th" to "<sup>th</sup>" when it's applied to an alias.
    For consistency, and also to make it easier to find all aliases
    (because now the closing '_' is always a word boundary).

Author: jmdyck