Apply suggestions from code review

Co-authored-by: Hans Ekkehard Plesser <hans.ekkehard.plesser@nmbu.no>

Author: jougs

build_support/check_code_style.sh

@@ -273,7 +273,7 @@ if $PERFORM_CLANG_FORMAT; then
   $CLANG_FORMAT -style=file ./nest/main.cpp >/dev/null 2>&1 || error_exit "Failed to verify the CLANG-FORMAT installation. Executable: $CLANG_FORMAT"
   clang_format_version=`$CLANG_FORMAT --version | sed -${EXTENDED_REGEX_PARAM} 's/^.*([0-9]\.[0-9])\..*/\1/'`
   if [[ "x$clang_format_version" != "x13.0" ]]; then
-    error_exit "Failed to verify the CLANG-FORMAT installation. Version 13 is required. The executable '$CLANG_FORMAT' is of version $clang_format_version."
+    error_exit "Failed to verify the CLANG-FORMAT installation. Version 13.0 is required. The executable '$CLANG_FORMAT' is version $clang_format_version."
   fi
 fi
 

doc/htmldoc/developer_space/guidelines/coding_guidelines_check.rst

@@ -41,7 +41,7 @@ The code has to compile without warnings (in the default settings of the build
 infrastructure). We restrict ourselves to the C++11 standard for a larger support of
 compilers on various cluster systems and supercomputers.
 
-We use clang-format version 13 in our CI.
+We use clang-format version 13 in our CI. If your `clang-format` executable is not version 13, you need to specify an executable with version 13 explicitly with the `--clang-format` option to ensure consistency with the NEST CI.
 
 Furthermore, we use `Vera++ <https://bitbucket.org/verateam/vera/wiki/Home>`_, which
 'is a programmable tool for verification, analysis and transformation of C++