doc: fix egregious markup output

We use '+++' syntax to output a literal '**' for a '--glob' example.
This '+++' syntax is pretty ugly when rendered literally via --help. We
fix this by hackily inserting the '+++' syntax for its one specific case
that we need it during man page generation.

Not ideal but it works. And --help still has some '*foo*' markup, but we
live with that for now.

Fixes #1581

CHANGELOG.md

@@ -1,3 +1,13 @@
+TBD
+===
+Unreleased changes. Release notes have not yet been written.
+
+Bug fixes:
+
+* [BUG #1581](https://github.com/BurntSushi/ripgrep/issues/1581):
+  Corrects some egregious markup output in `--help`.
+
+
 12.1.0 (2020-05-09)
 ===================
 ripgrep 12.1.0 is a small minor version release that mostly includes bug fixes

build.rs

@@ -217,6 +217,10 @@ fn formatted_doc_txt(arg: &RGArg) -> io::Result<String> {
         .doc_long
         .replace("{", "&#123;")
         .replace("}", r"&#125;")
+        // Hack to render ** literally in man page correctly. We can't put
+        // these crazy +++ in the help text directly, since that shows
+        // literally in --help output.
+        .replace("*-g 'foo/**'*", "*-g +++'foo/**'+++*")
         .split("\n\n")
         .map(|s| s.to_string())
         .collect();

crates/core/app.rs

@@ -1354,7 +1354,7 @@ command line takes precedence.
 When this flag is set, every file and directory is applied to it to test for
 a match. So for example, if you only want to search in a particular directory
 'foo', then *-g foo* is incorrect because 'foo/bar' does not match the glob
-'foo'. Instead, you should use *-g +++'foo/**'+++*.
+'foo'. Instead, you should use *-g 'foo/**'*.
 "
     );
     let arg = RGArg::flag("glob", "GLOB")