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.

lib/questionlib.php

@@ -2079,7 +2079,7 @@ function get_next_version(int $questionbankentryid): int {
  * @param string $questionbankentryid Entry to check against.
  * @return bool
  */
-function is_latest(string $version, string $questionbankentryid) : bool {
+function is_latest(string $version, string $questionbankentryid): bool {
     global $DB;
 
     $sql = 'SELECT MAX(version) AS max