Add 'vendor-specific markup' to index

chapters/annotations.tex

@@ -322,7 +322,10 @@ \subsubsection{Text Markup in Captions}\label{text-markup-in-captions}
 not supported, and any paragraph break before the first paragraph or after the last
 paragraph has no impact.)
 
-Vendor-specific markup takes the form \lstinline!%__$\mathit{nameOfVendor}_{1}$($\mathit{data}_{1}$)$\ldots$__$\mathit{nameOfVendor}_{n}$($\mathit{data}_{n}$)[$\mathit{text}$]!, where $n \geq 1$.  The $\mathit{nameOfVendor}$ consists of only digits and letters, and shall only convey the name of the vendor defining the meaning of the associated $\mathit{data}$.  Text markup escape sequences don't apply inside the $\mathit{data}$, implying that it cannot contain the closing parenthesis, `)'.  A tool which does not understand any of the vendor-specific meanings shall only display the mandatory $\mathit{text}$, but the $\mathit{text}$ may also be used together with the vendor-specific $\mathit{data}$.
+\firstuse{Vendor-specific markup}\index{vendor-specific markup} takes the form \lstinline!%__$\mathit{nameOfVendor}_{1}$($\mathit{data}_{1}$)$\ldots$__$\mathit{nameOfVendor}_{n}$($\mathit{data}_{n}$)[$\mathit{text}$]!, where $n \geq 1$.
+The $\mathit{nameOfVendor}$ consists of only digits and letters, and shall only convey the name of the vendor defining the meaning of the associated $\mathit{data}$.
+Text markup escape sequences don't apply inside the $\mathit{data}$, implying that it cannot contain the closing parenthesis, `)'.
+A tool which does not understand any of the vendor-specific meanings shall only display the mandatory $\mathit{text}$, but the $\mathit{text}$ may also be used together with the vendor-specific $\mathit{data}$.
 
 \begin{example}
 One application of vendor-specific markup is to prototype a feature that can later be turned into standardized markup.  For example, say that the tool AVendor wants to generalize the variable replacements such that the duration of a simulation can be substituted into a caption.  During the development, this could be represented as the vendor-specific markup \lstinline!%__AVendor(?duration)[10 s]!, if the simulation has a duration of 10~seconds at the time of writing the caption.  When AVendor renders this, it ignores the text \lstinline!10 s! and just displays the actual duration instead.  Later, if this would become supported by standard markup, it might take the form of something like \lstinline!%{experiment:duration}! instead (note that \lstinline!experiment:duration! is not in the form of a component reference, avoiding conflict with current use of variable replacements).