Add remark on boundedness perfect complexes

Thanks to Nicolás
https://stacks.math.columbia.edu/tag/08CM#comment-8373

cohomology.tex

@@ -12482,6 +12482,11 @@ \section{Perfect complexes}
 if it can be represented by a perfect complex of $\mathcal{O}_X$-modules.
 \end{definition}
 
+\noindent
+If $X$ is quasi-compact, then a perfect object of $D(\mathcal{O}_X)$
+is in $D^b(\mathcal{O}_X)$. But this need not be the case if
+$X$ is not quasi-compact.
+
 \begin{lemma}
 \label{lemma-perfect-independent-representative}
 Let $(X, \mathcal{O}_X)$ be a ringed space.

sites-cohomology.tex

@@ -12707,6 +12707,12 @@ \section{Perfect complexes}
 if it can be represented by a perfect complex of $\mathcal{O}$-modules.
 \end{definition}
 
+\noindent
+If $\Sh(\mathcal{C})$ is quasi-compact
+(Sites, Section \ref{sites-section-quasi-compact}),
+then a perfect object of $D(\mathcal{O})$
+is in $D^b(\mathcal{O})$. But this need not be the case otherwise.
+
 \begin{lemma}
 \label{lemma-perfect-independent-representative}
 Let $(\mathcal{C}, \mathcal{O})$ be a ringed site.