Merge branch 'bc/doc-adoc-not-txt'

All the documentation .txt files have been renamed to .adoc to help content aware editors. * bc/doc-adoc-not-txt: Remove obsolete ".txt" extensions for AsciiDoc files doc: use .adoc extension for AsciiDoc files gitattributes: mark AsciiDoc files as LF-only editorconfig: add .adoc extension doc: update gitignore for .adoc extension