Exclude infix applications from leaf-func-expr fallback in getAllCurriedArgsAtPosition

The rangeContainsPos fallback (for narrowed symbol-use ranges) was
matching infix operator applications like "a === b" where pos points
at the operator. This caused parameter name hints to appear for custom
operators used in infix position.

Fix: Gate the fallback on 'not isInfix' so it only applies to prefix
function applications (dotted accesses, qualified names), which was
the original intent.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: T-Gro

src/Compiler/Service/ServiceParamInfoLocations.fs

@@ -483,8 +483,11 @@ module internal SynExprAppLocationsImpl =
                     // pos may point at the terminal identifier rather than the full long-id start.
                     // The second condition handles this by checking whether pos falls within the
                     // leaf function expression's range in the application chain.
-                    | SynExpr.App(_exprAtomicFlag, _isInfix, funcExpr, argExpr, range) when
-                        posEq pos range.Start || rangeContainsPos (getLeafFuncExpr funcExpr).Range pos
+                    // We exclude infix applications from the fallback to avoid matching operator
+                    // uses like "a === b" where pos points at the operator.
+                    | SynExpr.App(_exprAtomicFlag, isInfix, funcExpr, argExpr, range) when
+                        posEq pos range.Start
+                        || (not isInfix && rangeContainsPos (getLeafFuncExpr funcExpr).Range pos)
                         ->
                         let isInfixFuncExpr =
                             match funcExpr with