Fix misspelled Utf8NullTerminatedStringStartsWithAsciiPrefix
Fix comment typos in MemoryBlock
Fix misspelled test Utf8NullTerminatedStringStartsWithAsciiPrefix
System.Xml.XDocument Typos

System.Xml.XDocument Typos removed tabs in typo fixes
System.Xml.XmlDocument Typos

System.Xml.XmlDocument removed tabs from typo fixes
System.Xml.XPath Typos

System.Xml.XPath removed tabs in typo fixes

System.Xml.XPath undo wrong typo fix
System.Xml.XPath.XmlDocument Typos
System.Reflection.Metadata Typos
System.Numerics.Vectors Typos

System.Numerics.Vectors removed tabs in typo fixes
System.Collections.Immutable Typos

System.Collections.Immutable removed tabs from typo fixes
Remove unnecessary allocations from Keys, Values, and ContainsValue members
Named consts in PLINQ
Merge pull request #152 from jzebedee/proofreading

Fixes misspelled methods, tests, and comments
Merge pull request #172 from stephentoub/immut_allocs

Remove allocations from Keys/Values/ContainsValue members
Merge pull request #177 from AndreyAkinshin/PLinqNamedConsts

Named consts in PLINQ
Merge pull request #150 from sgtfrankieboy/master

Typo fixes in Comments / Summaries