Fix some typos in the static access shorthand proposal

[sgrekhov]

• <selector*> changed to <selector>*
• "Expressions of the forms .new<typeArgs> or .new<typeArgs> ..." changed to "Expressions of the forms .new<typeArgs>(args) or .new<typeArgs> ..."
• "If an expression has the form e1 == e2 or e1 != e2, or a pattern has the form == e2,..." added "... or != e2,..."
• " Static tear-offs are constant. Instantiated static tear-offs are constant if the inferred type arguments are. that is not a constant expression.)" - removed "that is not a constant expression.)"