[Search git log] improve compatibility with older git versions (#151)

The git log format placeholder %as wasn't added until Git 2.25.0. Unfortunately, people are often stuck on older Git versions (one possibility is that their git binary is managed by their company). To resolve this, we swap out %as with %ad but pass in --date=short.

functions/__fzf_search_git_log.fish

@@ -6,11 +6,11 @@ function __fzf_search_git_log --description "Search the output of git log and pr
         # See similar comment in __fzf_search_shell_variables.fish.
         set --local --export SHELL (command --search fish)
 
-        set log_fmt_str '%C(bold blue)%h%C(reset) - %C(cyan)%as%C(reset) %C(yellow)%d%C(reset) %C(normal)%s%C(reset)  %C(dim normal)[%an]%C(reset)'
+        # see documentation for git format placeholders at https://git-scm.com/docs/git-log#Documentation/git-log.txt-emnem
+        # %h gives you the abbreviated commit hash, which is useful for saving screen space, but we will have to expand it later below
+        set log_fmt_str '%C(bold blue)%h%C(reset) - %C(cyan)%ad%C(reset) %C(yellow)%d%C(reset) %C(normal)%s%C(reset)  %C(dim normal)[%an]%C(reset)'
         set selected_log_line (
-            # see documentation for git format placeholders at https://git-scm.com/docs/git-log#Documentation/git-log.txt-emnem
-            # %h gives you the abbreviated commit hash, which is useful for saving screen space, but we will have to expand it later below
-            git log --color=always --format=format:$log_fmt_str | \
+            git log --color=always --format=format:$log_fmt_str --date=short | \
             fzf --ansi \
                 --tiebreak=index \
                 --preview='git show --color=always {1}' \