Issue #26665: Remove mis-use of ``$`` in activate.fish.

This is a revertion of cfc66e37eb8e.

Thanks to 鄭景文 for the bug report. Thanks to Tin Tvrtković, Xiang
Zhang, and Dan McCombs for diagnosing the issue.

Lib/venv/scripts/posix/activate.fish

@@ -55,8 +55,8 @@ if test -z "$VIRTUAL_ENV_DISABLE_PROMPT"
     # with the original prompt function renamed, we can override with our own.
     function fish_prompt
         # Prompt override?
-        if test -n "$__VENV_PROMPT__"
-            printf "%s%s%s" "$__VENV_PROMPT__" (set_color normal) (_old_fish_prompt)
+        if test -n "__VENV_PROMPT__"
+            printf "%s%s%s" "__VENV_PROMPT__" (set_color normal) (_old_fish_prompt)
             return
         end
         # ...Otherwise, prepend env

Misc/NEWS

@@ -13,6 +13,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #26664: Fix activate.fish by removing mis-use of ``$``.
+
 - Issue #22115: Fixed tracing Tkinter variables: trace_vdelete() with wrong
   mode no longer break tracing, trace_vinfo() now always returns a list of
   pairs of strings, tracing in the "u" mode now works.