.{editorconfig,gitattributes,pre-commit-config.yaml}: add comment to beginning for more details

I know what the files do, but do my readers? Especially when I am using these files as templates for new repositories?

.editorconfig

@@ -1,3 +1,4 @@
+# See https://editorconfig.org for more information
 # Note: I use this file as ~/.editorconfig when something doesn't specify to
 # be root before reaching ~, so this contains files not seen in this repo
 root = true

.gitattributes

@@ -1,3 +1,4 @@
+# See https://www.git-scm.com/docs/gitattributes#_effects for more information
 *	text=auto eol=lf linguist-detectable
 
 # These files are scary, let's not touch them

.pre-commit-config.yaml

@@ -1,3 +1,5 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.ci for more information
 ci:
   # Attempts to use networking and fails at name resolution, local hook
   # skip: [bundler-audit, pylint]