pathspec: fix typo "glossary-context.txt" -> "glossary-content.txt"

The pathspec syntax is explained in the file "glossary-content.txt".
Moreover, no file named "glossary-context.txt" exists in the repository.

Signed-off-by: Abhijeet Sonar <abhijeet.nkt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: quanta-kt

pathspec.h

@@ -23,7 +23,7 @@ struct index_state;
 #define PATHSPEC_ONESTAR 1	/* the pathspec pattern satisfies GFNM_ONESTAR */
 
 /**
- * See glossary-context.txt for the syntax of pathspec.
+ * See glossary-content.txt for the syntax of pathspec.
  * In memory, a pathspec set is represented by "struct pathspec" and is
  * prepared by parse_pathspec().
  */