Add tasks for all the new languages

Task/String-matching/Phix/string-matching.phix

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+constant word = "the",                                      -- (also try this with "th"/"he")
+         sentence = "the last thing the man said was the"
+--       sentence = "thelastthingthemansaidwasthe"          -- (practically the same results)
+
+-- A common, but potentially inefficient idiom for checking for a substring at the start is:
+if match(word,sentence)=1 then
+    ?"yes(1)"
+end if
+-- A more efficient method is to test the appropriate slice
+if length(sentence)>=length(word)
+and sentence[1..length(word)]=word then
+    ?"yes(2)"
+end if
+-- Which is almost identical to checking for a word at the end
+if length(sentence)>=length(word)
+and sentence[-length(word)..-1]=word then
+    ?"yes(3)"
+end if
+-- Or sometimes you will see this, a tiny bit more efficient:
+if length(sentence)>=length(word)
+and match(word,sentence,length(sentence)-length(word)+1) then
+    ?"yes(4)"
+end if
+-- Finding all occurences is a snap:
+integer r = match(word,sentence)
+while r!=0 do
+    ?r
+    r = match(word,sentence,r+1)
+end while