Merge branch 'dn/gpg-doc' into maint

The documentation tries to consistently spell "GPG"; when
referring to the specific program name, "gpg" is used.

* dn/gpg-doc:
  Documentation: GPG capitalization

Documentation/git-tag.txt

@@ -78,7 +78,7 @@ OPTIONS
 
 -v::
 --verify::
-	Verify the gpg signature of the given tag names.
+	Verify the GPG signature of the given tag names.
 
 -n<num>::
 	<num> specifies how many lines from the annotation, if any,

Documentation/git-verify-commit.txt

@@ -12,7 +12,7 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-Validates the gpg signature created by 'git commit -S'.
+Validates the GPG signature created by 'git commit -S'.
 
 OPTIONS
 -------