Merge #939: fix typo: builders-key -> builder-keys

0a9d233 fix typo: builders-key -> builder-keys (stickies-v)

Pull request description:

  The underlying URL is not affected, only the link text is wrong

  The full link is https://github.com/bitcoin/bitcoin/tree/master/contrib/builder-keys/keys.txt

ACKs for top commit:
  katesalazar:
    ACK 0a9d233
  Zero-1729:
    crACK 0a9d233

Tree-SHA512: ef8e0fcb2994e36a2eb3617252cda152c6bde09e509286c70bcabd7308dc7301901d637a9339d31070328d0b9bed916e5793da5918e853b15ce7eef583c2c37b

Author: fanquake

_posts/en/pages/2017-01-01-download.md

@@ -90,7 +90,7 @@ obtain_release_key: >
   into your GPG key database.</p>
 
   <p>For example, given the <a href='$(BUILDER_KEYS_TXT_URL)'><code>
-  builders-key/keys.txt</code></a> line
+  builder-keys/keys.txt</code></a> line
   <code>$(EXAMPLE_BUILDERS_LINE)</code>you could load that
   key using this command:</p>
 

_posts/es/pages/2017-01-01-download.md

@@ -93,7 +93,7 @@ obtain_release_key: >
   cargar en tu base de datos de claves GPG.</p>
 
   <p>Por ejemplo, dada la línea <a href='$(BUILDER_KEYS_TXT_URL)'><code>
-  builders-key/keys.txt</code></a>
+  builder-keys/keys.txt</code></a>
   <code>$(EXAMPLE_BUILDERS_LINE)</code> podrías cargar esa clave usando este
   comando:</p>