Allow negative numbers in the template grammar

This allows negative numbers, which also means functions which took numbers can now take negative numbers

Luckily, they all already handled this exactly as expected.

cli/src/template.pest

@@ -25,8 +25,8 @@ raw_literal = @{ literal_char+ }
 literal = { "\"" ~ (raw_literal | escape)* ~ "\"" }
 
 integer_literal = {
-  ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*
-  | "0"
+  "-"? ~ ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*
+  | "-"? ~ "0"
 }
 
 identifier = @{ (ASCII_ALPHA | "_") ~ (ASCII_ALPHANUMERIC | "_")* }

cli/tests/test_log_command.rs

@@ -632,6 +632,16 @@ fn test_log_shortest_length_parameter() {
     @  2
     ◉  0
     "###);
+    insta::assert_snapshot!(
+        test_env.jj_cmd_success(&repo_path, &["log", "-T", "commit_id.shortest(-0)"]), @r###"
+    @  2
+    ◉  0
+    "###);
+    insta::assert_snapshot!(
+        test_env.jj_cmd_success(&repo_path, &["log", "-T", "commit_id.shortest(-100)"]), @r###"
+    @  2
+    ◉  0
+    "###);
     insta::assert_snapshot!(
         test_env.jj_cmd_success(&repo_path, &["log", "-T", "commit_id.shortest(100)"]), @r###"
     @  230dd059e1b059aefc0da06a2e5a7dbf22362f22

cli/tests/test_templater.rs

@@ -164,6 +164,14 @@ fn test_templater_parse_error() {
       |
       = Method "foo" doesn't exist for type "Integer"
     "###);
+    insta::assert_snapshot!(render_err(r#"(-empty)"#), @r###"
+    Error: Failed to parse template:  --> 1:2
+      |
+    1 | (-empty)
+      |  ^---
+      |
+      = expected template
+    "###);
 
     insta::assert_snapshot!(render_err(r#"("foo" ++ "bar").baz()"#), @r###"
     Error: Failed to parse template:  --> 1:18
@@ -516,6 +524,66 @@ fn test_templater_fill_function() {
     over the lazy dog
     "###);
 
+    // A low value will not chop words, but can chop a label by words
+    insta::assert_snapshot!(
+        render(r#"fill(9, "Longlonglongword an some short words " ++
+                       label("error", "longlonglongword and short words") ++ " back out\n")"#),
+        @r###"
+    Longlonglongword
+    an some
+    short
+    words
+    longlonglongword
+    and short
+    words
+    back out
+    "###);
+
+    // Filling to 0 means breaking at every word
+    insta::assert_snapshot!(
+        render(r#"fill(0, "The quick fox jumps over the " ++
+                       label("error", "lazy") ++ " dog\n")"#),
+        @r###"
+    The
+    quick
+    fox
+    jumps
+    over
+    the
+    lazy
+    dog
+    "###);
+
+    // Filling to -0 is the same as 0
+    insta::assert_snapshot!(
+        render(r#"fill(-0, "The quick fox jumps over the " ++
+                       label("error", "lazy") ++ " dog\n")"#),
+        @r###"
+    The
+    quick
+    fox
+    jumps
+    over
+    the
+    lazy
+    dog
+    "###);
+
+    // Filling to negatives are clamped to the same as zero
+    insta::assert_snapshot!(
+        render(r#"fill(-10, "The quick fox jumps over the " ++
+                       label("error", "lazy") ++ " dog\n")"#),
+        @r###"
+    The
+    quick
+    fox
+    jumps
+    over
+    the
+    lazy
+    dog
+    "###);
+
     // Word-wrap, then indent
     insta::assert_snapshot!(
         render(r#""START marker to help insta\n" ++