Fix extraneous quotes in unexpected EOF CSS parser errors. b=299192 r+sr=bzbarsky a=asa

dom/locales/en-US/chrome/layout/css.properties

@@ -37,7 +37,7 @@
 MimeNotCss=The stylesheet %1$S was not loaded because its MIME type, "%2$S", is not "text/css".
 MimeNotCssWarn=The stylesheet %1$S was loaded as CSS even though its MIME type, "%2$S", is not "text/css".
 
-PEUnexpEOF=Unexpected end of file while searching for '%1$S'.
+PEUnexpEOF=Unexpected end of file while searching for %1$S.
 PEParseRuleWSOnly=Whitespace-only string given to be parsed as rule.
 PEDeclDropped=Declaration dropped.
 PEDeclSkipped=Skipped to next declaration.