Move _all.do -> all.do and slightly update docs.

all.do's main job was to print a "nothing much to do" message after
running.  Nowadays it actually does do stuff, so we can remove the
warning, making _all.do redundant.

README.md

@@ -8,8 +8,8 @@ version, so other people have implemented different variants based on his
 published specification.
 
 This version, sometimes called apenwarr/redo, is probably the most advanced
-one, including support for parallel builds, improved logging, and helpful
-debugging features.
+one, including parallel builds, improved logging, extensive automated tests,
+and helpful debugging features.
 
 To build and test redo, run `./do -j10 test`.  To install it, run
 `DESTDIR=/tmp/testinstall PREFIX=/usr/local ./do -j10 install`.
@@ -19,6 +19,6 @@ To build and test redo, run `./do -j10 test`.  To install it, run
 - View the [documentation](https://redo.rtfd.io) via readthedocs.org
 - Visit the [source code](https://github.com/apenwarr/redo) on github
 - Discussions and support via the
-    [mailing list](https://groups.google.com/group/redo-list).
+    mailing list ([archives](https://groups.google.com/group/redo-list)).
     You can subscribe by sending any email message to
     `[email protected]` (note the plus sign).

all.do

@@ -1,2 +1,9 @@
-redo-ifchange _all
-echo "Nothing much to do.  Try 'bin/redo -j10 test'" >&2
+if [ "$1,$2" != "all,all" ]; then
+	echo "ERROR: old-style redo args detected: don't use --old-args." >&2
+	exit 1
+fi
+
+# Do this first, to ensure we're using a good shell
+redo-ifchange redo/sh
+
+redo-ifchange bin/all docs/all

docs/index.md

@@ -33,8 +33,7 @@ easier that way.
 I also provide an extremely minimal pure-POSIX-sh implementation, called
 `do`, in the `minimal/` directory of this repository.
 
-(Want to discuss redo?  See the bottom of this file for
-information about our mailing list.)
+(Want to discuss redo?  Join [our mailing list](Contributing/#mailing-list).)
 
 
 # What's so special about redo?

install.do

@@ -13,7 +13,7 @@ if [ "$DESTDIR" = "NONE" ]; then
 	exit 99
 fi
 
-redo-ifchange _all redo/whichpython
+redo-ifchange all redo/whichpython
 read py <redo/whichpython
 
 echo "Installing to: $DESTDIR$PREFIX"

test.do

@@ -1,2 +1,2 @@
 redo-ifchange bin/all
-redo minimal/test docs/test t/all _all
+redo minimal/test docs/test t/all all