Fix stackoverflow during doc generation

On some systems, previous usage of `match` may cause a stackoverflow
(presumably due to the large size of the match result). Avoid this by
(ab)using `replaceStrings` to test for containment without using
regexes, thereby avoiding the issue. The causal configuration seems to
be the stack size hard limit, which e.g. Amazon Linux sets, whereas most
Linux distros leave unlimited.

Match the fn name to similar fn in nixpkgs.lib, but different
implementation that does not use `match`. This impl gives perhaps
unexpected results when the needle is `""`, but the scope of this is
narrow and that case is a bit odd anyway.

This makes for some duplication-of-work as we do a different
`replaceStrings` if this one is true, but this only runs during doc
generation at build time so has no runtime impact.

See https://github.com/NixOS/nix/issues/11085 for details.

doc/manual/generate-manpage.nix

@@ -116,9 +116,12 @@ let
             storeInfo = commandInfo.stores;
             inherit inlineHTML;
           };
+          hasInfix = infix: content:
+            builtins.stringLength content != builtins.stringLength (replaceStrings [ infix ] [ "" ] content);
         in
         optionalString (details ? doc) (
-          if match ".*@store-types@.*" details.doc != null
+          # An alternate implementation with builtins.match stack overflowed on some systems.
+          if hasInfix "@store-types@" details.doc
           then help-stores
           else details.doc
         );