help: Fix superscript page style

Replace 'e.g.' with 'such as'.

Ref: #185

help/C/superscript.page

@@ -19,7 +19,7 @@
 	<title>Superscript and Subscript</title>
 
     <p>
-    Some equations may require numbers to be entered in superscript or subscript form. e.g.
+    Some equations may require numbers to be entered in superscript or subscript form, such as:
     </p>
     <example>
     <p>
@@ -35,6 +35,6 @@
     To enter superscript numbers use <keyseq><key>Ctrl</key>number</keyseq>, for subscript numbers use <keyseq><key>Alt</key>number</keyseq>. 
     </p>
     <p>
-    The number mode returns to normal when entering the next non-number character (e.g. +, -).
+    The number mode returns to normal when entering the next non-number character, such as "+" or "-".
     </p>
 </page>