Improve the auto-fixing for DocComment.ShortFullStop coding standard

Problem/Motivation

The sniff Drupal.Commenting.DocComment.ShortFullStop auto-fixes short comments by adding a period when the line does not end in one. The current coded logic will add a period if the line does not end in .  !  ? or ) and is also not {@inheritDoc} and does not match the base filename.

This produces odd fixes which are not correct and require manual fixing. Some examples in Core files:

--- a/core/core.api.php
+++ b/core/core.api.php
 /**
- * Prepares a message based on parameters;
+ * Prepares a message based on parameters;.
  *

--- a/core/lib/Drupal/Core/Entity/Query/ConditionFundamentals.php
+++ b/core/lib/Drupal/Core/Entity/Query/ConditionFundamentals.php
   /**
-   * The conjunction of this condition group. The value is one of the following:
+   * The conjunction of this condition group. The value is one of the following:.
    *

--- a/core/modules/workspaces/tests/src/Kernel/WorkspaceTestTrait.php
+++ b/core/modules/workspaces/tests/src/Kernel/WorkspaceTestTrait.php
    *   - dev
    *     - local_1
    *     - local_2
-   * - qa
+   * - qa.
    */
   protected function createWorkspaceHierarchy() {

Novice programmers assume that anything Coder produces will be correct and this had led to lots of review effort being spent in Core issues. It would be better not to attempt the fix when we can determine that the resulting change is not very good and will just require manual intervention. In these cases we should just report the error, and let the developer fix it correctly first time.

See #2572635-4: Fix 'Drupal.Commenting.DocComment.LongFullStop' coding standard comments #4 and #9-11 for examples of the incorrect fixes and unnecessary review time. This sniff can be improved too in the same way.

Proposed resolution

• If the short comment does not end with an alpha-numeric character then do not attempt the fix.
• If the short comment includes a newline do not attempt the fix. The fact that it spans on to more than one line is reported by ShortSingleLine and will likely require a re-write of the comment text. Then if it does not end in a period this will be checked by LongFullStop anyway.

Remaining tasks

1. Determine if the allowed set of ending characters .  !  ? or ) is correct. Are there more to add? Should some be removed?
2. Code the change to the fixer as and when agreed
3. Test on core files to determine the impact

In #3183673: Fix 'Drupal.Commenting.DocComment.ShortFullStop' coding standard - part 1 auto-fixes I am working on fixing the Core files. That issue can be used to show work-in-progress.