PHP: Added missing PHP 7.4 fn keyword (#2858)

Author: danon

components/prism-php.js

@@ -112,7 +112,7 @@
 				//
 				// keywords cannot be preceded by "->"
 				// the complex lookbehind means `(?<!(?:->|::)\s*)`
-				pattern: /((?:^|[^\s>:]|(?:^|[^-])>|(?:^|[^:]):)\s*)\b(?:__halt_compiler|abstract|and|array|as|break|callable|case|catch|clone|const|continue|declare|default|die|do|echo|else|elseif|empty|enddeclare|endfor|endforeach|endif|endswitch|endwhile|enum|eval|exit|extends|final|finally|for|foreach|function|global|goto|if|implements|include|include_once|instanceof|insteadof|interface|isset|list|namespace|match|new|or|parent|print|private|protected|public|require|require_once|return|self|static|switch|throw|trait|try|unset|use|var|while|xor|yield)\b/i,
+				pattern: /((?:^|[^\s>:]|(?:^|[^-])>|(?:^|[^:]):)\s*)\b(?:__halt_compiler|abstract|and|array|as|break|callable|case|catch|clone|const|continue|declare|default|die|do|echo|else|elseif|empty|enddeclare|endfor|endforeach|endif|endswitch|endwhile|enum|eval|exit|extends|final|finally|fn|for|foreach|function|global|goto|if|implements|include|include_once|instanceof|insteadof|interface|isset|list|namespace|match|new|or|parent|print|private|protected|public|require|require_once|return|self|static|switch|throw|trait|try|unset|use|var|while|xor|yield)\b/i,
 				lookbehind: true
 			}
 		],

components/prism-php.min.js

@@ -30,6 +30,7 @@ exit
 extends;
 final
 finally
+fn
 for
 foreach
 function
@@ -109,6 +110,7 @@ yield from
 	["keyword", "extends"], ["punctuation", ";"],
 	["keyword", "final"],
 	["keyword", "finally"],
+	["keyword", "fn"],
 	["keyword", "for"],
 	["keyword", "foreach"],
 	["keyword", "function"],