Fix typo in core/INSTALL.txt file

Problem/Motivation

Typo mistake in a core/INSTALL.txt file in Drupal core.
defaults.settings.php should be default.settings.php.

Proposed resolution

Replace defaults.settings.php to default.settings.php.

Remaining tasks

1. Create patch
2. Review/RTBC
3. Commit

User interface changes

None.

API changes

None.

Data model changes

None.

Release notes snippet

Fixed typo in core/INSTALL.txt file

Original report by sandeepscs

Typo mistake in a core/INSTALL.txt file in Drupal core. defaults.settings.php should be default.settings.php.

We can add the following code to resolve this problem.

diff --git a/core/INSTALL.txt b/core/INSTALL.txt
old mode 100644
new mode 100755
index cf8019f..e3e7bb4
--- a/core/INSTALL.txt
+++ b/core/INSTALL.txt
@@ -405,7 +405,7 @@ The new directory name is constructed from the site's URL. The configuration
for www.example.com could be in 'sites/example.com/settings.php' (note that
'www.' should be omitted if users can access your site at http://example.com/).

- $ cp sites/default/defaults.settings.php sites/example.com/settings.php
+ $ cp sites/default/default.settings.php sites/example.com/settings.php

Sites do not have to have a different domain. You can also use subdomains and
subdirectories for Drupal sites. For example, example.com, sub.example.com, and
s