MDL-65292 style: Fix all function declarations white space

This has been generated running the following Sniffs, all
them part of the Moodle's CodeSniffer standard:
- PSR12.Functions.ReturnTypeDeclaration
- PSR12.Functions.NullableTypeDeclaration
- moodle.Methods.MethodDeclarationSpacing
- Squiz.Whitespace.ScopeKeywordSpacing

All them are, exclusively, about correct spacing, so the changes
are, all them, only white space changes.

Only exceptions to the above are 3 changes what were setting the
return type in a new line, and, when that happens, the closing
parenthesis (bracket) has to go to the same line than the colon.

grade/import/csv/tests/load_data_test.php

@@ -513,7 +513,7 @@ Bobby,Bunce,,"Moodle HQ","Rock on!",[email protected],75.00,,75.00,{exportdat
     /*
      * Test importing csv data into the gradebook using "Last downloaded from this course" column and force import option.
      */
-    public function test_force_import_option () {
+    public function test_force_import_option() {
 
         // Need to add users into the system.
         $user = new \stdClass();