minor #26134 Document explicitly that dotfiles and vcs files are ignored by default (mnapoli)

This PR was submitted for the master branch but it was merged into the 2.7 branch instead (closes #26134).

Discussion
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Document explicitly that dotfiles and vcs files are ignored by default

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | ?
| Fixed tickets | None
| License       | MIT
| Doc PR        | N/A

This change makes it clear whether or not each of those two options are enabled by default.

Without this documentation one has to look into the code.

---

For documentation PRs should I target master or the same branch as bugs?

Commits
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e25b988 Document explicitly that dotfiles and vcs files are ignored by default

Author: nicolas-grekas

Finder.php

@@ -402,6 +402,8 @@ public function exclude($dirs)
     /**
      * Excludes "hidden" directories and files (starting with a dot).
      *
+     * This option is enabled by default.
+     *
      * @param bool $ignoreDotFiles Whether to exclude "hidden" files or not
      *
      * @return $this
@@ -422,6 +424,8 @@ public function ignoreDotFiles($ignoreDotFiles)
     /**
      * Forces the finder to ignore version control directories.
      *
+     * This option is enabled by default.
+     *
      * @param bool $ignoreVCS Whether to exclude VCS files or not
      *
      * @return $this