Remaining erratas and errata-like issues

[Tpt]

I ignore here everything related to EXISTS:

• errata-query-6 - fix / errors in aggregates (substantive)
• errata-query-14 - clarification: explanation of "unaggregated variables" (editorial)
• errata-query-16 - suggested change that SAMPLE should return a term and not an error if possible (substantive)
• errata-query-17
  Correct section 5.1.1 Blank Node Labels
  Correct section 19.6 Blank Nodes and Blank Node Labels - basic graph pattern should be TriplesBlock
• errata-query-20 - fix : distinct and project should preserve order
• errata-query-21 - fix : "no group" aggregation

Relevant issues:

• Fix GROUP BY definition when no GROUP BY clause is present  #105
• Clarify handling of invalid codepoint escape sequences #164
• Trailing VALUES should be the last translation step. #215
• Mis-alignment of prefix handling #220
• Definition of evaluation of solution modifiers formally incorrect #222
• eval function undefined for multisets and sequences of solution mappings #225
• Translation of property path patterns incomplete #226
• Notion of "ordering condition" undefined #229
• 'Group' and 'Aggregation' should not be operators of the algebraic syntax #230
• bug in translation when gathering FILTER expresssions #249
• Inconsistencies in definition of evaluation of property path with sequence #266
• Bug in definition of evaluation of property path with OneOrMorePath #267
• Evaluation of Minus is missing #269
• STRLEN definition based on F&O seems incomplete #271
• Multiplicity undefined for Extend operator #290
• 1.2 draft spec language changes semantics of CONCAT #297
• Symbol L in 'Evaluation Semantics' section should not be a solution sequence #308