Add tasks for all the new languages

Task/Literals-String/Phix/literals-string-1.phix

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+constant UPPERCASEJ = 'J'   -- equivalent to 74

Task/Literals-String/Phix/literals-string-2.phix

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+constant hw = "Hello World!",
+         mt = ""    -- empty string

Task/Literals-String/Phix/literals-string-3.phix

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+s = "日本語"

Task/Literals-String/Phix/literals-string-4.phix

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+string s = "food"
+    s[2..3] = 'e'       -- s is now "feed" (replace all)
+    s[2..2] = "east"    -- s is now "feasted" (replace substring)
+    s[2..5] = ""        -- s is now "fed"

Task/Literals-String/Phix/literals-string-5.phix

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+ts = """
+this
+string\thing"""
+
+ts = """
+_____this
+     string\thing"""
+
+ts = 'this
+string\thing'
+
+ts = "this\nstring\\thing"

Task/Literals-String/Phix/literals-string-6.phix

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+?x"68 65 6c 6c 6f";     -- displays "hello"