Fix typo for small pi (#7296)

Author: k3KAW8Pnf7mkmdSMPHz27

src/main/java/org/jabref/logic/util/strings/HTMLUnicodeConversionMaps.java

@@ -270,7 +270,7 @@ public class HTMLUnicodeConversionMaps {
             {"957", "nu", "$\\nu$"}, // greek small letter nu, U+03BD ISOgrk3
             {"958", "xi", "$\\xi$"}, // greek small letter xi, U+03BE ISOgrk3
             {"959", "omicron", "$\\omicron$"}, // greek small letter omicron, U+03BF NEW
-            {"960", "pi", "$\\phi$"}, // greek small letter pi, U+03C0 ISOgrk3
+            {"960", "pi", "$\\pi$"}, // greek small letter pi, U+03C0 ISOgrk3
             {"961", "rho", "$\\rho$"}, // greek small letter rho, U+03C1 ISOgrk3
             {"962", "sigmaf", "$\\varsigma$"}, // greek small letter final sigma,
             //                                   U+03C2 ISOgrk3