Cosmetic fix in doc/user/markdown.md where the word 'itself' is repeated.

doc/user/markdown.md

@@ -1292,7 +1292,7 @@ Example:
 Additionally, you can choose the alignment of text within columns by adding colons (`:`)
 to the sides of the "dash" lines in the second row. This will affect every cell in the column.
 
-> Note that the headers are always right aligned [within GitLab itself itself](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#tables).
+> Note that the headers are always right aligned [within GitLab itself](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#tables).
 
 ```markdown
 | Left Aligned | Centered | Right Aligned | Left Aligned | Centered | Right Aligned |