Add all of `rust-bitcoin`'s lints

[luisschwab]

Add all of the lints below, one at a time. When a PR adding a lint lands, ping me here so I can scratch it off.

[lints.rust]

• missing_docs = "warn"

[lints.clippy]

• needless_question_mark = "allow"
• manual_range_contains = "allow" # More readable than clippy's format.
• assigning_clones = "warn"
• bool_to_int_with_if = "warn"
• borrow_as_ptr = "warn"
• case_sensitive_file_extension_comparisons = "warn"
• cast_lossless = "warn"
• cast_possible_truncation = "allow" # All casts should include a code comment (except test code).
• cast_possible_wrap = "allow" # Same as above re code comment.
• cast_precision_loss = "warn"
• cast_ptr_alignment = "warn"
• cast_sign_loss = "allow" # All casts should include a code comment (except in test code).
• checked_conversions = "warn"
• cloned_instead_of_copied = "warn"
• copy_iterator = "warn"
• default_trait_access = "warn"
• doc_link_with_quotes = "warn"
• doc_markdown = "warn"
• empty_enums = "warn"
• enum_glob_use = "warn"
• expl_impl_clone_on_copy = "warn"
• explicit_deref_methods = "warn"
• explicit_into_iter_loop = "warn"
• explicit_iter_loop = "warn"
• filter_map_next = "warn"
• flat_map_option = "warn"
• float_cmp = "allow" # Bitcoin floats are typically limited to 8 decimal places and we want them exact.
• fn_params_excessive_bools = "warn"
• if_not_else = "warn"
• ignored_unit_patterns = "warn"
• implicit_clone = "warn"
• implicit_hasher = "warn"
• inconsistent_struct_constructor = "warn"
• index_refutable_slice = "warn"
• inefficient_to_string = "warn"
• inline_always = "warn"
• into_iter_without_iter = "warn"
• invalid_upcast_comparisons = "warn"
• items_after_statements = "warn"
• iter_filter_is_ok = "warn"
• iter_filter_is_some = "warn"
• iter_not_returning_iterator = "warn"
• iter_without_into_iter = "warn"
• large_digit_groups = "warn"
• large_futures = "warn"
• large_stack_arrays = "warn"
• large_types_passed_by_value = "warn"
• linkedlist = "warn"
• macro_use_imports = "warn"
• manual_assert = "warn"
• manual_instant_elapsed = "warn"
• manual_is_power_of_two = "warn"
• manual_is_variant_and = "warn"
• manual_let_else = "warn"
• manual_ok_or = "warn"
• manual_string_new = "warn"
• many_single_char_names = "warn"
• map_unwrap_or = "warn"
• match_bool = "allow" # Adds extra indentation and LOC.
• match_same_arms = "allow" # Collapses things that are conceptually unrelated to each other.
• match_wild_err_arm = "warn"
• match_wildcard_for_single_variants = "warn"
• maybe_infinite_iter = "warn"
• mismatching_type_param_order = "warn"
• missing_errors_doc = "warn"
• missing_fields_in_debug = "warn"
• missing_panics_doc = "warn"
• missing_safety_doc = "warn"
• missing_docs_in_private_items = "warn"
• must_use_candidate = "allow" # Useful for audit but many false positives.
• mut_mut = "warn"
• naive_bytecount = "warn"
• needless_bitwise_bool = "warn"
• needless_continue = "warn"
• needless_for_each = "warn"
• needless_pass_by_value = "warn"
• needless_raw_string_hashes = "warn"
• no_effect_underscore_binding = "warn"
• no_mangle_with_rust_abi = "warn"
• option_as_ref_cloned = "warn"
• option_option = "warn"
• ptr_as_ptr = "warn"
• ptr_cast_constness = "warn"
• pub_underscore_fields = "warn"
• range_minus_one = "warn"
• range_plus_one = "warn"
• redundant_clone = "warn"
• redundant_closure_for_method_calls = "warn"
• redundant_else = "warn"
• ref_as_ptr = "warn"
• ref_binding_to_reference = "warn"
• ref_option = "warn"
• ref_option_ref = "warn"
• return_self_not_must_use = "warn"
• same_functions_in_if_condition = "warn"
• semicolon_if_nothing_returned = "warn"
• should_panic_without_expect = "warn"
• similar_names = "allow" # Too many (subjectively) false positives.
• single_char_pattern = "warn"
• single_match_else = "warn"
• stable_sort_primitive = "warn"
• str_split_at_newline = "warn"
• string_add_assign = "warn"
• struct_excessive_bools = "warn"
• struct_field_names = "allow" # dumb
• too_many_lines = "warn"
• transmute_ptr_to_ptr = "warn"
• trivially_copy_pass_by_ref = "warn"
• unchecked_time_subtraction = "warn"
• unicode_not_nfc = "warn"
• uninlined_format_args = "allow" # This is a subjective style choice.
• unnecessary_box_returns = "warn"
• unnecessary_join = "warn"
• unnecessary_literal_bound = "warn"
• unnecessary_wraps = "warn"
• unnested_or_patterns = "warn"
• unreadable_literal = "warn"
• unsafe_derive_deserialize = "warn"
• unused_async = "warn"
• unused_self = "warn"
• use_self = "warn" [Add and apply use_self = deny lint #1122]
• used_underscore_binding = "warn"
• used_underscore_items = "warn"
• verbose_bit_mask = "warn"
• wildcard_imports = "warn"
• zero_sized_map_values = "warn"