Revert "[MAX Examples] move from StringLiteral to StaticString

This reverts commit 628c40a8200c548a3563c00ecc4311c451587827, it broke
some tests that are in presubmits.

MODULAR_ORIG_COMMIT_REV_ID: e20bb7963a54f2543a9f8306ff0321a9ab02ff6b

Author: lattner

examples/custom_ops/kernels/add_custom.mojo

@@ -23,7 +23,7 @@ struct AddConstantCustom[value: Int]:
     @staticmethod
     fn execute[
         # e.g. "CUDA" or "CPU"
-        target: StaticString,
+        target: StringLiteral,
     ](
         out: OutputTensor,
         x: InputTensor[type = out.type, rank = out.rank],
@@ -53,7 +53,7 @@ struct AddOneCustom:
     @staticmethod
     fn execute[
         # The kind of device this will be run on: "cpu" or "gpu"
-        target: StaticString,
+        target: StringLiteral,
     ](
         out: OutputTensor,
         x: InputTensor[type = out.type, rank = out.rank],

examples/custom_ops/kernels/fused_attention.mojo

@@ -83,7 +83,7 @@ struct FusedAttention:
         D: Int,  # Head dimension
         BN: Int,  # Dimension of blocks to split Q into
         BD: Int,  # Dimension of blocks to split K, V into
-        target: StaticString,  # "cpu" or "gpu"
+        target: StringLiteral,  # "cpu" or "gpu"
     ](
         output: OutputTensor[type=dtype, rank=rank],
         key: InputTensor[type=dtype, rank=rank],
@@ -210,7 +210,7 @@ fn fused_attention_cpu[
 
 @always_inline
 fn matmul[
-    target: StaticString,
+    target: StringLiteral,
     transpose_b: Bool = False,
 ](
     lhs: LayoutTensor,

examples/custom_ops/kernels/histogram.mojo

@@ -99,7 +99,7 @@ fn _histogram_gpu(
 struct Histogram:
     @staticmethod
     fn execute[
-        target: StaticString
+        target: StringLiteral
     ](
         out: OutputTensor[type = DType.int64, rank=1],
         input: InputTensor[type = DType.uint8, rank=1],

examples/custom_ops/kernels/mandelbrot.mojo

@@ -29,7 +29,7 @@ struct Mandelbrot:
     @staticmethod
     fn execute[
         # The kind of device this will be run on: "cpu" or "gpu"
-        target: StaticString,
+        target: StringLiteral,
     ](
         out: OutputTensor,
         # starting here are the list of inputs

examples/custom_ops/kernels/matrix_multiplication.mojo

@@ -778,7 +778,7 @@ struct MatrixMultiplication[algorithm: StringLiteral]:
     @staticmethod
     fn execute[
         # The kind of device this will be run on: "cpu" or "gpu"
-        target: StaticString,
+        target: StringLiteral,
     ](
         out: OutputTensor[rank=2],
         a: InputTensor[type = out.type, rank = out.rank],

examples/custom_ops/kernels/top_k.mojo

@@ -52,7 +52,7 @@ struct TopK:
         rank: Int,
         //,  # Forces the previous two params to be inferred from the args
         K: Int,
-        target: StaticString,
+        target: StringLiteral,
     ](
         out_vals: OutputTensor[type=dtype, rank=rank],
         out_idxs: OutputTensor[type = DType.int32, rank=rank],

examples/custom_ops/kernels/vector_addition.mojo

@@ -75,7 +75,7 @@ struct VectorAddition:
     @staticmethod
     fn execute[
         # The kind of device this will be run on: "cpu" or "gpu"
-        target: StaticString,
+        target: StringLiteral,
     ](
         out: OutputTensor[rank=1],
         lhs: InputTensor[type = out.type, rank = out.rank],

mojo/stdlib/src/builtin/_format_float.mojo

@@ -1689,7 +1689,7 @@ alias float8_e5m2_to_str = StaticTuple[StaticString, 256](
     "nan",
 )
 
-alias float8_e4m3fn_to_str = StaticTuple[StaticString, 256](
+alias float8_e4m3fn_to_str = StaticTuple[StringLiteral, 256](
     "0.0",
     "0.001953125",
     "0.00390625",