Fix typo in 02.equations.md (#30)

Fix typo: delimeters → delimiters

Closes #25

content/02.equations.md

@@ -1,6 +1,6 @@
 ### Equations
 
-Numbered equations can be included by using `$$` delimeters with embedded LaTeX math.
+Numbered equations can be included by using `$$` delimiters with embedded LaTeX math.
 Equations can be labeled with tags like this `{#eq:label}` and referenced in text using `@eq:label`.
 
 $$ y = mx + b $$ {#eq:line}