LaTeX writer: Improve grouping with autocites.

Closes #8088.

src/Text/Pandoc/Writers/LaTeX/Citation.hs

@@ -171,8 +171,9 @@ citationsToBiblatex inlineListToLaTeX (c:cs)
       return $ text cmd <> mconcat groups
 
   where grouper prev cit = case prev of
-         ((CiteGroup oPfx oSfx ids):rest)
-             | null oSfx && null pfx -> CiteGroup oPfx sfx (cid:ids) : rest
+         ((CiteGroup oPfx [] ids):rest)
+             | null pfx && null sfx
+           -> CiteGroup oPfx sfx (cid:ids) : rest
          _ -> CiteGroup pfx sfx [cid] : prev
          where pfx = citationPrefix cit
                sfx = citationSuffix cit

test/command/5849-prefix.md

@@ -20,7 +20,7 @@
 % pandoc -t latex --biblatex
 [e.g. @a1;@a2, ch.3 and elsewhere;@a3; but also @a4;@a5]
 ^D
-\autocites[e.g.][ch.3 and elsewhere]{a1,a2}{a3}[but also][]{a4,a5}
+\autocites[e.g.][]{a1}[ch.3 and elsewhere]{a2}{a3}[but also][]{a4,a5}
 ```
 ```
 % pandoc -t latex --biblatex

test/command/8088.md

@@ -0,0 +1,6 @@
+```
+% pandoc -t latex --biblatex
+[@first, 1; @second; @third, 3]
+^D
+\autocites[1]{first}{second}[3]{third}
+```