Update Git documentation (2.51.0)

Author: simon04

lib/docs/scrapers/git.rb

@@ -1,7 +1,7 @@
 module Docs
   class Git < UrlScraper
     self.type = 'git'
-    self.release = '2.50.0'
+    self.release = '2.51.0'
     self.base_url = 'https://git-scm.com/docs'
     self.initial_paths = %w(
       /git.html