Fix outdated Java version in task 11a

exercises/footnotes/footnotes.code.done.tex

@@ -1,7 +1,5 @@
-Java is an object-oriented programming language that appeared in 
-1995. The most recent version of the programming language is 
-version 20\footnote{March 2023}. In order to write Java programs, 
-one needs to install the so-called \emph{Java Development Kit 
-(JDK)}.\footnote{\url{https://www.oracle.com/java/technologies/javase-downloads.html}}
-Java programs can be written independently from the operating 
-system that one uses.
+Java is an object-oriented programming language that appeared in 1995. 
+The most recent long-term support version of the programming language is Java SE 21 \footnote{released in September 2023}.
+In order to write Java programs, one needs to install the so-called \emph{Java Development Kit 
+(JDK)}\footnote{\url{https://www.oracle.com/java/technologies/javase-downloads.html}}.
+Java programs can be written independently from the operating system that one uses.

exercises/footnotes/footnotes.raw.tex

@@ -1 +1,3 @@
-Java is an object-oriented programming language that appeared in 1995. The most recent version of the programming language is version 20 (March 2023). In order to write Java programs, one needs to install the so-called \emph{Java Development Kit (JDK)}. Java programs can be written independently from the operating system that one uses.
+% !TeX root = ../../main-exercises.tex
+
+Java is an object-oriented programming language that appeared in 1995. The most recent long-term support version of the programming language is Java SE 21 (released in September 2023). In order to write Java programs, one needs to install the so-called \emph{Java Development Kit (JDK)}. Java programs can be written independently from the operating system that one uses.

exercises/footnotes/task.tex

@@ -2,7 +2,5 @@
 
 \subsection{Inserting footnotes}
 
-Make the text \enquote{March 2023} of the file 
-\file{exercises/footnotes/footnotes.tex} appear as a footnote instead of in 
-parentheses. Additionally, insert a clickable URL to the Java Development Kit 
-as footnote: \\ \texttt{https://www.oracle.com/java/technologies/javase-downloads.html}
+Make the text \enquote{released in September 2023} of the file \file{exercises/footnotes/footnotes.tex} appear as a footnote instead of in parentheses. 
+Additionally, insert a clickable URL to the Java Development Kit as footnote: \\ \texttt{https://www.oracle.com/java/technologies/javase-downloads.html}

exercises/graphics/graphics.raw.tex

@@ -1 +1,3 @@
+% !TeX root = ../../main-exercises.tex
+
 Please insert the image here.

exercises/lists/lists.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 Ingredients:
 400~g berries, 50~ml maple syrup, 4~lemons, 1~l cold water, 400~g ice cubes
 

exercises/literature/literature.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 An introductory \LaTeX{} course can be found in \enquote{\LaTeX{} in 24 Hours} (Datta, 2017).
 There is a plethora of further handbooks (e.\,g., Goossens, Mittelbach and Samarin, 2002).
 

exercises/maths/math-formulas.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 Replace this graphic by the corresponding formulas:
 
 \vspace{1cm} % some additional spacing before the image

exercises/references/references.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 C\# is an object-oriented programming language that was developed by Microsoft in 2011. In the figure we can see the logo of the programming language.  
 
 \begin{figure}[H]

exercises/source-code-listings/source-code-listings.raw.tex

@@ -1 +1,3 @@
+% !TeX root = ../../main-exercises.tex
+
 Your listings go here.

exercises/special-characters/special-characters.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 What is a semester ticket?
 It is also known as Studi-Ticket or Studi-Karte and allows you to use the local public transport around Bamberg for free.
 In Bamberg, your student card (Studierendenausweis) is used, i. a., as a semester ticket.

exercises/tables/tables.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 \begin{itemize}
 	\item Foundations of Software Engineering
 	\subitem abbreviation: SWT-FSE-B

exercises/text-markup/markup.raw.tex

@@ -1,3 +1,5 @@
+% !TeX root = ../../main-exercises.tex
+
 ``Recursion (adjective: recursive) occurs when a thing is defined in terms of itself or of its type.
 Recursion is used in a variety of disciplines ranging from linguistics to logic.
 The most common application of recursion is in mathematics and computer science,