io.pathnames: Revised ~ support to expand on the first tilde, and not on "~/".

This mimics the same behaviour as "ls ~" in the shell, which expands the alias
as a directory, and not as a filename. For the specific edge-case where a
filename called "~" must have a path constructed to it (e.g. "./~" or "~/~").

core/io/pathnames/pathnames-docs.factor

@@ -106,7 +106,7 @@ HELP: absolute-path
     { "path" "a pathname string" }
     { "path'" "a pathname string" }
 }
-{ $description "Prepends the " { $link current-directory } " to the pathname and resolves a " { $snippet "resource:" } ", " { $snippet "~/" } " or " { $snippet "vocab:" } " prefix, if present (see " { $link "io.pathnames.special" } ")." }
+{ $description "Prepends the " { $link current-directory } " to the pathname and resolves a " { $snippet "resource:" } ", " { $snippet "~" } " or " { $snippet "vocab:" } " prefix, if present (see " { $link "io.pathnames.special" } ")." }
 { $notes "This word is exactly the same as " { $link normalize-path } ", except on Windows NT platforms, where it does not prepend the Unicode path prefix. Most code should call " { $link normalize-path } " instead." } ;
 
 HELP: resolve-symlinks
@@ -133,7 +133,7 @@ ARTICLE: "io.pathnames.special" "Special pathnames"
 $nl
 "If a pathname begins with " { $snippet "vocab:" } ", then it will be searched for in all current vocabulary roots (see " { $link "add-vocab-roots" } ")."
 $nl
-"If a pathname begins with " { $snippet "~/" } ", it will be searched for in the home directory. Subsequent tildes in the pathname will be construed as literal tilde path or filenames and will not be treated specially. It should be noted that the " { $snippet "~" } " symbol without a forward slash will be also be treated as a literal path or filename." ;
+"If a pathname begins with " { $snippet "~" } ", it will be searched for in the home directory. Subsequent tildes in the pathname will be construed as literal tilde path or filenames and will not be treated specially. To access a filename named " { $snippet "~" } ", you must construct a path to reference the filename, even if it's within the current directory such as " { $snippet "./~" } "." ;
 
 ARTICLE: "io.pathnames.presentations" "Pathname presentations"
 "Pathname presentations are objects that wrap a pathname string. Clicking a pathname presentation in the UI brings up the file in one of the supported editors. See " { $link "editor" } " for more details."

core/io/pathnames/pathnames-tests.factor

@@ -1,6 +1,7 @@
 USING: io.pathnames io.files.temp io.directories
 continuations math io.files.private kernel
-namespaces sequences tools.test io.pathnames.private ;
+namespaces sequences system tools.test 
+io.backend io.pathnames.private ;
 IN: io.pathnames.tests
 
 [ "passwd" ] [ "/etc/passwd" file-name ] unit-test
@@ -71,8 +72,14 @@ IN: io.pathnames.tests
 [ f ] [ "/funny.directory/file-with-no-extension" file-extension ] unit-test
 [ "" ] [ "/funny.directory/file-with-no-extension." file-extension ] unit-test
 
-! Testing ~/ special pathname
-[ t ] [ "~/" absolute-path home = ] unit-test 
-[ f ] [ "~" absolute-path home = ] unit-test
-[ t ] [ "~/~" absolute-path "/~" home prepend = ] unit-test
-[ t ] [ "~/~/" absolute-path "/~/" home prepend = ] unit-test
+! Testing ~ special pathname
+[ t ] [ os windows? "~\\" "~/" ? absolute-path home = ] unit-test 
+[ t ] [ "~/" home [ normalize-path ] bi@ = ] unit-test 
+
+[ t ] [ "~" absolute-path home = ] unit-test
+[ t ] [ "~" home [ normalize-path ] bi@ = ] unit-test 
+
+[ t ] [ "~" home [ "foo" append-path ] bi@ [ normalize-path ] bi@ = ] unit-test
+[ t ] [ os windows? "~\\~/" "~/~/" ? "~" "~" append-path [ path-components ] bi@ = ] unit-test
+
+

core/io/pathnames/pathnames.factor

@@ -152,7 +152,7 @@ M: string absolute-path
             trim-head-separators vocab-path
             absolute-path
         ] [
-            "~/" ?head [
+            "~" ?head [
                 trim-head-separators home prepend-path
                 absolute-path
         ] [