allow to force installing a clangd and qtcreator files

Add a forceclangd target to Makefile to force installing a .clangd file.
Add a forceqtcreator target to force installing qtcreator files.
Existing files will be overwritten.

while here:
- update the c++ standard to c++23

.templates/install_qtcreator.sh

@@ -6,6 +6,14 @@ QTCREATOR_DIR=${CURRENT_DIR}/.qtcreator
 
 # ----------
 
+has_force_arg=0
+
+if [ $# -eq 1 ] ; then
+	if [ $1 == 'force' ] ; then
+		has_force_arg=1
+	fi
+fi
+
 # make sure the current directory is correct
 if [ ! -d ${CURRENT_DIR}/.templates ] ; then
 	echo "this script should be called by make: make qtcreator (one level up)"
@@ -48,6 +56,10 @@ GLOBAL_WORKING_DIR_FOR_SED=$(echo ${GLOBAL_WORKING_DIR} | sed 's/\//\\\//g')
 
 was_qtcreator_dir=0
 
+if [ $has_force_arg -eq 1 ] ; then
+	rm -rf "${QTCREATOR_DIR}"
+fi
+
 if [ -d "${QTCREATOR_DIR}" ] ; then
 	was_qtcreator_dir=1
 else
@@ -76,7 +88,7 @@ if [ -d "${QTCREATOR_DIR}" ] ; then
 
 			if [ $was_qtcreator_dir -eq 0 ] ; then
 				echo "QTCreator files generated to ${QTCREATOR_DIR} directory"
-				echo "select an 'open project...' option and find a ${QTCREATOR_DIR}/*.creator file"
+				echo "In QTCreator select an 'open project...' option and find a ${QTCREATOR_DIR}/*.creator file"
 			fi
 
 		fi
@@ -96,4 +108,3 @@ if [ -d "${QTCREATOR_DIR}" ] ; then
 
 fi
 
-