Update definition-lists.md (#1221)

Author: lcawl

docs/syntax/definition-lists.md

@@ -1,7 +1,7 @@
-# Definition Lists
+# Definition lists
 
 
-A Definition List in Markdown is created by writing a term on one line, followed by a colon and at least one space (`: `) on the next line, followed by the definition. Multiple paragraphs in the definition should be indented with spaces to match the definition text.
+A definition list in Markdown is created by writing a term on one line, followed by a colon and at least three spaces (`:   `) on the next line, followed by the definition. Multiple paragraphs in the definition should be indented with spaces to match the definition text.
 
 
 ## Basic definition list