Implement clang-format in pre-commit

Clang-format config changes 120 column limit

Replace unknown charecter with '

Add clang-format to config.yaml

Update jenkins and .pre-commit-config.yaml to work with pre-commit

.clang-format

-BasedOnStyle: LLVM
 
+---
+BasedOnStyle: LLVM
+---
+Language: Cpp
+ColumnLimit: 120
+...

.pre-commit-config.yaml

@@ -16,4 +16,10 @@ repos:
         args: ['--maxkb=4096']
       - id: check-xml
       - id: check-yaml
+        args: [--allow-multiple-documents]
 
+  - repo: https://github.com/mantidproject/pre-commit-hooks
+    rev: 05b2d4cfe17dcb36e29c249705364c19eeccced5
+    hooks:
+      - id: clang-format
+        exclude: Testing/Tools/cxxtest|tools
\ No newline at end of file

Framework/Kernel/src/Matrix.cpp

@@ -1020,7 +1020,7 @@ yes invert the matrix using analytic formula. If not then use standard Invert
     }
   }
   if (regular) {
-    // use analytic expression as described in G Y Hu and R F OConnell (1996)
+    // use analytic expression as described in G Y Hu and R F O'Connell (1996)
     T scalefactor = numRows() > 1 ? m_rawData[1][0] : 1;
     *this /= scalefactor;
     T D = m_rawData[0][0];

buildconfig/Jenkins/clangformat

@@ -6,6 +6,12 @@
 
 # clang-format executable
 
+# Rely on pre-commit if clang format is in the config.yaml
+if grep -F "id: clang-format" $WORKSPACE/.pre-commit-config.yaml; then
+  echo "Pre-commit will handle clang-format. Skipping check."
+  exit 0
+fi
+
 SCRIPT_DIR=$(dirname "$0")
 if [[ ${JOB_NAME} == *pull_requests* ]]; then
     # This relies on the fact pull requests use pull/$PR-NAME