Fix projectile-replace on Emacs 27+ (#1748, #1741)

Two bugs in projectile-replace:

1. fileloop is autoloaded but never required, so (fboundp
   #'fileloop-continue) returns nil and the function falls back to the
   legacy Emacs 25/26 code path even on Emacs 27+.  Fix by requiring
   fileloop before the check.

2. fileloop-initialize-replace expects a regexp, but projectile-replace
   is documented to do literal replacement.  Fix by wrapping the search
   term with regexp-quote.

Author: bbatsov

CHANGELOG.md

@@ -8,6 +8,8 @@
 
 ### Bugs fixed
 
+* [#1748](https://github.com/bbatsov/projectile/issues/1748): Fix `projectile-replace` falling back to the legacy Emacs 25/26 code path on Emacs 27+ because `fileloop` was not loaded.
+* [#1741](https://github.com/bbatsov/projectile/issues/1741): Fix `projectile-replace` treating the search string as a regexp instead of a literal string on Emacs 27+.
 * [#1897](https://github.com/bbatsov/projectile/issues/1897): Filter deleted-but-unstaged files from `git ls-files` output in alien/hybrid indexing (when `fd` is not used).
 * [#1873](https://github.com/bbatsov/projectile/issues/1873): Skip unreadable directories during native indexing instead of aborting with a permission error.
 * [#1961](https://github.com/bbatsov/projectile/issues/1961): Prevent directories from matching file-type project root markers (e.g., a `workspace` directory no longer matches the `WORKSPACE` Bazel marker on case-insensitive filesystems).

projectile.el

@@ -4960,9 +4960,10 @@ on which to run the replacement."
                     (projectile-prepend-project-name
                      (format "Replace %s with: " old-text))))
          (files (projectile-files-with-string old-text directory file-ext)))
+    (require 'fileloop nil t)
     (if (fboundp #'fileloop-continue)
         ;; Emacs 27+
-        (progn (fileloop-initialize-replace old-text new-text files 'default)
+        (progn (fileloop-initialize-replace (regexp-quote old-text) new-text files 'default)
                (fileloop-continue))
       ;; Emacs 25 and 26
       ;;