revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/refspec.h

@@ -20,22 +20,6 @@ struct refspec_item {
 #define REFSPEC_INIT_FETCH { .fetch = REFSPEC_FETCH }
 #define REFSPEC_INIT_PUSH { .fetch = REFSPEC_PUSH }
 
-/**
- * A struct refspec holds the parsed interpretation of a refspec.  If it will
- * force updates (starts with a '+'), force is true.  If it is a pattern
- * (sides end with '*') pattern is true.  src and dest are the two sides
- * (including '*' characters if present); if there is only one side, it is src,
- * and dst is NULL; if sides exist but are empty (i.e., the refspec either
- * starts or ends with ':'), the corresponding side is "".
- *
- * An array of strings can be parsed into an array of struct refspecs using
- * parse_fetch_refspec() or parse_push_refspec().
- *
- * remote_find_tracking(), given a remote and a struct refspec with either src
- * or dst filled out, will fill out the other such that the result is in the
- * "fetch" specification for the remote (note that this evaluates patterns and
- * returns a single result).
- */
 struct refspec {
 	struct refspec_item *items;
 	int alloc;