Wrap --help output and use pager

Set clap option `max_term_width`, so the help output is by default as
wide as the terminal or this max value. Then manually wrap the
`after_long_help()` text (only on demand) to the same width using
`textwrap`. Also use matching ansi codes in this section.

The help output is now paginated if output is to a terminal.

All code paths flow back to main() so an invoked pager is properly
waited for (by the OutputType drop impl).

Cargo.toml

@@ -55,6 +55,7 @@ unicode-width = "0.1.10"
 xdg = "2.4.1"
 clap_complete = "4.4.4"
 terminal-colorsaurus = "0.4.1"
+textwrap = { version = "0.16.0", default-features = false, features = [] }
 
 [dependencies.git2]
 version = "0.18.2"

manual/src/full---help-output.md

@@ -790,7 +790,11 @@ Similarly, the default value of --line-numbers-right-format is '{np:^4}│'. Thi
 Use '<' for left-align, '^' for center-align, and '>' for right-align.
 
 
+SUPPORT
+-------
+
 If something isn't working correctly, or you have a feature request, please open an issue at https://github.com/dandavison/delta/issues.
 
+
 For a short help summary, please use delta -h.
 ```

src/ansi/mod.rs

@@ -12,8 +12,10 @@ use iterator::{AnsiElementIterator, Element};
 
 pub const ANSI_CSI_CLEAR_TO_EOL: &str = "\x1b[0K";
 pub const ANSI_CSI_CLEAR_TO_BOL: &str = "\x1b[1K";
+pub const ANSI_SGR_BOLD: &str = "\x1b[1m";
 pub const ANSI_SGR_RESET: &str = "\x1b[0m";
 pub const ANSI_SGR_REVERSE: &str = "\x1b[7m";
+pub const ANSI_SGR_UNDERLINE: &str = "\x1b[4m";
 
 pub fn strip_ansi_codes(s: &str) -> String {
     strip_ansi_codes_from_strings_iterator(ansi_strings_iterator(s))