Update chapters/revisions.tex

Co-authored-by: Elena Shmoylova <eshmoylova@users.noreply.github.com>

chapters/revisions.tex

@@ -1,7 +1,7 @@
 \chapter{Modelica Revision History}\label{modelica-revision-history}
 
 This appendix described the history of the Modelica Language Design, and its contributors.
-This appendix is just present for historic reasons and is not normative.
+This appendix is just present for historical reasons and is not normative.
 The current version of this document is available from \url{https://modelica.org/documents}.
 All versions of this document, and the list of changes is available at \url{https://specification.modelica.org}.