only report a failure from pygmentize as a warning, not an error

It shouldn’t fail to generate the documentation just because
pygmentize doesn’t recognize the language used in the code
block. Instead it should just output an unhilighted code block
containing the text.

Author: db48x

src/render.rs

@@ -1,6 +1,7 @@
 use crate::config::Config;
 use crate::doctest;
 use crate::parser;
+use crate::report::report_warning;
 
 use serde::Serialize;
 use std::collections::HashMap;
@@ -95,12 +96,15 @@ pub fn process_markdown(
                 }
 
                 // Pygmentize was chosen over syntect because it has way more themes and is customizable through a CSS stylesheet
-                let html =
-                    pygmentize::highlight(&code, Some(&code_lang), &HtmlFormatter::new()).unwrap();
-
+                let ret = match pygmentize::highlight(&code, Some(&code_lang), &HtmlFormatter::new()) {
+                    Ok(html) => Some(Event::Html(html.into())),
+                    Err(_) => {
+                        report_warning(&format!("Unable to create syntax highlighting for “{code_lang}” code block"));
+                        Some(Event::Code(code.clone().into()))
+                    },
+                };
                 code.clear();
-
-                Some(Event::Html(html.into()))
+                ret
             }
         }