cli: clarify "Now at: <commit>" message as "Working copy now at: <commit>"

I considered even changing the message to "Checking out: <commit>" as
that's technically more correct (the message is printed when the
view's checkout is updated, i.e. before the working copy is
updated). However, I worried that users would find it confusing that
e.g. `jj close` would result in a "Checking out: " message, even
though that's what actually happens.

README.md

@@ -121,7 +121,7 @@ Let's check out a different commit so we get some files to work with in the
 working copy:
 ```shell script
 $ jj co 080a9b37ff7e
-Now at: 608c179a60df
+Working copy now at: 608c179a60df
 added 84 files, modified 0 files, removed 0 files
 $ jj st
 Parent commit: 080a9b37ff7e cli: make `jj st` show parent commit before working copy commit
@@ -146,7 +146,7 @@ working on:
 # This will bring up $EDITOR (or `pico` by default). Enter something like
 # "Jujutsu is ready!" in the editor and then close it.
 $ jj describe
-Now at: b2985d68096d Jujutsu is ready!
+Working copy now at: b2985d68096d Jujutsu is ready!
 ```
 
 Now make the change in the README:
@@ -198,7 +198,7 @@ this. We'll get back to that when we talk about conflicts.)
 So, let's say we're now done with this commit, so we close it:
 ```shell script
 $ jj close
-Now at: 192b456b024b
+Working copy now at: 192b456b024b
 $ jj st
 Parent commit: fb563a4c6d26 Jujutsu is ready!
 Working copy : 192b456b024b
@@ -282,18 +282,18 @@ commits:
 ```shell script
 # Check out the grandparent of the working copy
 $ jj co ::@
-Now at: 9164f1d6a011
+Working copy now at: 9164f1d6a011
 added 0 files, modified 1 files, removed 0 files
 $ echo a > file1; jj close -m A
-Now at: 5be91b2b5b69
+Working copy now at: 5be91b2b5b69
 $ echo b1 > file1; jj close -m B1
-Now at: a0331f1eeece
+Working copy now at: a0331f1eeece
 $ echo b2 > file1; jj close -m B2
-Now at: fd571967346e
+Working copy now at: fd571967346e
 $ echo c > file2; jj close -m C
-Now at: 4ae1e0587eef
+Working copy now at: 4ae1e0587eef
 $ jj co ::::@
-Now at: 9195b6d2e8dc
+Working copy now at: 9195b6d2e8dc
 added 0 files, modified 1 files, removed 1 files
 $ jj l
 o <-- 9195b6d2e8dc 47684978bf4b martinvonz@google.com 2021-05-26 12:39:56.000 -07:00
@@ -342,7 +342,7 @@ resolved the conflict, we'll squash the conflict resolution into the conflicted
 B2. That might look like this:
 ```shell script
 $ jj co 0c305a9e6b27  # Replace the hash by what you have for B2
-Now at: 619f58d8a988
+Working copy now at: 619f58d8a988
 added 0 files, modified 1 files, removed 0 files
 $ cat file1
 <<<<<<<
@@ -355,7 +355,7 @@ b2
 $ echo resolved > file1
 $ jj squash
 Rebased 1 descendant commits
-Now at: e659edc4a9fc
+Working copy now at: e659edc4a9fc
 $ jj l
 o <-- e659edc4a9fc 461f38324592 martinvonz@google.com 2021-05-26 12:53:08.000 -07:00
 |
@@ -401,7 +401,7 @@ The most useful command is `jj op undo`, which will undo an operation. By
 default, it will undo the most recent operation. Let's try it:
 ```shell script
 $ jj op undo
-Now at: 41f0d2289b56
+Working copy now at: 41f0d2289b56
 $ jj l
 o <-- 41f0d2289b56 b1e3a4afde5e martinvonz@google.com 2021-05-26 12:52:39.000 -07:00
 |
@@ -431,14 +431,14 @@ commits. These commands require you to have `meld` installed for now
 content to test these commands, so let's create a few more commits:
 ```shell script
 $ jj co origin/main
-Now at: 61b0efa09dbe 
+Working copy now at: 61b0efa09dbe 
 added 0 files, modified 0 files, removed 1 files
 $ printf 'a\nb\nc\n' > file; jj close -m abc
-Now at: f9147a088c0d 
+Working copy now at: f9147a088c0d 
 $ printf 'A\nB\nc\n' > file; jj close -m ABC
-Now at: 9d97c5018b23 
+Working copy now at: 9d97c5018b23 
 $ printf 'A\nB\nC\nD\n' > file; jj close -m ABCD
-Now at: c5a985bc3f41 
+Working copy now at: c5a985bc3f41 
 $ jj l
 o <-- c5a985bc3f41 3568f6e332d5 martinvonz@google.com 2021-05-26 14:36:46.000 -07:00 
 | 
@@ -460,7 +460,7 @@ Now try that:
 ```shell script
 $ jj squash -i -r :@
 Rebased 1 descendant commits
-Now at: 4b4c714b36aa 
+Working copy now at: 4b4c714b36aa 
 ```
 That will bring up Meld with a diff of the changes in the "ABCD" commit. Modify
 the right side of the diff to have the desired end state in "ABC" by removing
@@ -486,7 +486,7 @@ checking it out.
 $ jj edit -r ::@
 Created 2423c134ea70 ABC
 Rebased 2 descendant commits
-Now at: d31c52e8ca41 
+Working copy now at: d31c52e8ca41 
 ```
 When Meld starts, edit the right side by e.g. adding something to the first
 line. Then close Meld. You can now inspect the rewritten commit with

src/commands.rs

@@ -506,7 +506,7 @@ fn update_working_copy(
             err
         ))
     })?;
-    ui.write("Now at: ")?;
+    ui.write("Working copy now at: ")?;
     ui.write_commit_summary(repo.as_repo_ref(), &new_commit)?;
     ui.write("\n")?;
     Ok(Some(stats))

tests/smoke_test.rs

@@ -90,7 +90,7 @@ fn smoke_test() {
         testutils::CommandRunner::new(&repo_path).run(vec!["describe", "-m", "add some files"]);
     assert_eq!(output.status, 0);
     let stdout_string = output.stdout_string();
-    let output_regex = Regex::new("^Now at: [[:xdigit:]]+ add some files\n$").unwrap();
+    let output_regex = Regex::new("^Working copy now at: [[:xdigit:]]+ add some files\n$").unwrap();
     assert!(
         output_regex.is_match(&stdout_string),
         "output was: {}",
@@ -101,7 +101,7 @@ fn smoke_test() {
     let output = testutils::CommandRunner::new(&repo_path).run(vec!["close"]);
     assert_eq!(output.status, 0);
     let stdout_string = output.stdout_string();
-    let output_regex = Regex::new("^Now at: [[:xdigit:]]+ \n$").unwrap();
+    let output_regex = Regex::new("^Working copy now at: [[:xdigit:]]+ \n$").unwrap();
     assert!(
         output_regex.is_match(&stdout_string),
         "output was: {}",