LaTeX: escape Unicode HEAVY CHECK MARK into latex macros

Closes: #3707

CHANGES

@@ -15,6 +15,7 @@ Features added
 
 Bugs fixed
 ----------
+* #3707: latex: no bold checkmark (✔) available.
 * #5605 If the documentation language is set to Chinese, English words could not
   be searched.
 

sphinx/util/texescape.py

@@ -37,6 +37,7 @@ tex_replacements = [
     ('→', r'\(\rightarrow\)'),
     ('‣', r'\(\rightarrow\)'),
     ('✓', r'\(\checkmark\)'),
+    ('✔', r'\(\pmb{\checkmark}\)'),
     # used to separate -- in options
     ('', r'{}'),
     # map some special Unicode characters to similar ASCII ones