Add "Terms and definitions" back to navigation bar

docs/terms-and-definitions.md

@@ -1,8 +1,9 @@
 # Terms and definitions
 
-To do:  Need to fill this in to align to the terms and definitions that apply in this revision of the specification. 
+ISO and IEC maintain terminological databases for use in standardization
+at the following addresses:
 
-ISO and IEC maintain terminological databases for use in standardization at the following addresses:
-
-* ISO Online browsing platform: available at [https://www.iso.org/obp](https://www.iso.org/obp)
-* IEC Electropedia: available at [http://www.electropedia.org/](http://www.electropedia.org/)
+- ISO Online browsing platform: available at
+  [https://www.iso.org/obp](https://www.iso.org/obp)
+- IEC Electropedia: available at
+  [http://www.electropedia.org/](http://www.electropedia.org/)

mkdocs.yml

@@ -37,8 +37,9 @@ nav:
 - '1. Scope': scope.md
 - '2. References': references.md
 - '3. Symbols': symbols.md
-- '4. Conformance': conformance.md
-- '5. Model and serializations': serializations.md
+- '4. Terms and definitions': terms-and-definitions.md
+- '5. Conformance': conformance.md
+- '6. Model and serializations': serializations.md
 - model:  # [MODEL_PLACEHOLDER], to be replaced by content from mkdocs-files.yml
 - annexes:
   - 'A. Changes from the previous standard': annexes/changes-from-previous-iso.md