line info for strformat + fix issue with typed templates (#21761)

* line info in strformat

* also fix #20381

(cherry picked from commit e5d0907a42)

tests/stdlib/tstrformat.nim

@@ -555,5 +555,16 @@ proc main() =
     doAssert &"""{(if true: "'" & "'" & ')' else: "")}""" == "'')"
     doAssert &"{(if true: \"\'\" & \"'\" & ')' else: \"\")}" == "'')"
     doAssert fmt"""{(if true: "'" & ')' else: "")}""" == "')"
+
+  block: # issue #20381
+    var ss: seq[string]
+    template myTemplate(s: string) =
+      ss.add s
+      ss.add s
+    proc foo() =
+      myTemplate fmt"hello"
+    foo()
+    doAssert ss == @["hello", "hello"]
+
 # xxx static: main()
 main()

tests/stdlib/tstrformatlineinfo.nim

@@ -0,0 +1,8 @@
+# issue #21759
+
+{.hint[ConvFromXToItselfNotNeeded]: on.}
+
+import std/strformat
+
+echo fmt"{string ""abc""}" #[tt.Hint
+        ^ conversion from string to itself is pointless]#