Allow opening quote after another punctuation char in typographer

close https://github.com/markdown-it/markdown-it/issues/643

lib/rules_core/smartquotes.js

@@ -114,8 +114,14 @@ function process_inlines(tokens, state) {
       }
 
       if (canOpen && canClose) {
-        // treat this as the middle of the word
+        // Replace quotes in the middle of punctuation sequence, but not
-        canOpen = false;
+        // in the middle of the words, i.e.:
+        //
+        // 1. foo " bar " baz - not replaced
+        // 2. foo-"-bar-"-baz - replaced
+        // 3. foo"bar"baz     - not replaced
+        //
+        canOpen = isLastPunctChar;
         canClose = isNextPunctChar;
       }
 

test/fixtures/markdown-it/smartquotes.txt

@@ -137,3 +137,10 @@ and “that”.</p>
 <p>“this” and<br>
 “that”.</p>
 .
+
+Should allow quotes adjacent to other punctuation characters, #643:
+.
+The dog---"'man's' best friend"
+.
+<p>The dog—“‘man’s’ best friend”</p>
+.