fix(markdown): remove blockquote from code fence lines when toggling off

.changeset/quiet-fences-unquote.md

@@ -0,0 +1,5 @@
+---
+"@stackoverflow/stacks-editor": patch
+---
+
+Remove the blockquote from code fence lines when toggling a blockquote off in markdown mode

src/commonmark/commands.ts

@@ -197,7 +197,7 @@ export function matchLeadingBlockCharacters(text: string) {
     // If text is not an ordered list block, check for other block types
     if (!match) {
         // TODO HACK assumes all non-ordered list block types are non-letter characters followed by a single space
-        match = /^[^a-zA-Z0-9]+\s{1}(?=[a-zA-Z0-9_*[!]|$)+/.exec(text)?.[0];
+        match = /^[^a-zA-Z0-9]+\s{1}(?=[a-zA-Z0-9_*[!`~]|$)+/.exec(text)?.[0];
     }
 
     return match || "";

test/commonmark/commands.test.ts

@@ -489,6 +489,18 @@ some text`;
                     "\nth"
                 );
             });
+
+            it("multi line, selection spanning a fenced code block", () => {
+                const content = "> ```\n> Some code\n> ```";
+                const state = createState(content, 0, content.length);
+                const command = commands.setBlockTypeCommand(">");
+
+                expect(state).transactionSuccess(
+                    command,
+                    "```\nSome code\n```",
+                    "```\nSome code\n```"
+                );
+            });
         });
 
         /* SWAP */
@@ -605,6 +617,11 @@ some text`;
 
             expect(command).toBe("## ");
         });
+
+        it("return blockquote leading characters before a code fence", () => {
+            expect(commands.matchLeadingBlockCharacters("> ```")).toBe("> ");
+            expect(commands.matchLeadingBlockCharacters("> ~~~")).toBe("> ");
+        });
     });
 
     describe("insertTagLinkCommand", () => {