Auto-format imports using Module granularity (#702)

Part of #155

This is going to be a fun one 😆 

I've pushed two preview commits: the first one imports using the `Crate`
granularity, the other one with `Module` granularity.

Disclaimer: I'm biased 😃 I've used this style since I started
using Rust and it's also being used by vast majority of projects in the
ecosystem that I've used or looked at; it's also used by the Rust
compiler, Cargo and the tools like Rustfmt or Clippy.

Here's a summary of the possible options:
rust-lang/rustfmt#3362.

Here is an RFC discussion about setting on a variant:
rust-lang/style-team#140, I highly recommend
reading it.
To give a brief summary, it seems that people stand behind two options:
- `Module` - good trade-off between readability and conciseness
- `Item` - minimizes conflicts when many people edit the same files
often

To bring back some of the arguments raised in favor of the `Module` and
explain some of my reasoning as well:
- it naturally settles on the module as the, well, module/boundary from
which items can be imported...
- thus, helps build the intuition how to use and structure Rust crates
- less verbose than Java-style (`Item`) imports, which can often explode
and take unreasonable amount of space (and we don't really benefit
enough from minimized conflicts as we probably won't be a team of 50 or
the like)...
- but repeats enough information to quickly trace a module path rather
than having to reconstruct the paths from the `crate`-style use import
tree...
- and already often takes less space in our case, line-wise;
- quite good `grep`pability

Author: Xanewok

.rustfmt.toml

@@ -2,3 +2,4 @@
 # https://github.com/rust-lang/rustfmt/blob/master/Configurations.md
 
 group_imports = "StdExternalCrate"
+imports_granularity = "Module"

.vscode/settings.json

@@ -9,6 +9,9 @@
   "rust-analyzer.check.allTargets": true,
   "rust-analyzer.check.command": "clippy",
   "rust-analyzer.check.features": "all",
+  "rust-analyzer.imports.granularity.enforce": true,
+  "rust-analyzer.imports.granularity.group": "module",
+  "rust-analyzer.imports.prefix": "crate",
   "rust-analyzer.rustfmt.extraArgs": [
     "+nightly-2023-12-01" // Keep in sync with other "RUST_NIGHTLY_VERSION" references
   ],

crates/codegen/ebnf/src/precedence_parser.rs

@@ -1,6 +1,7 @@
 use codegen_schema::types::{OperatorModel, PrecedenceParserRef};
 
-use crate::{nodes::EbnfNode, EbnfSerializer};
+use crate::nodes::EbnfNode;
+use crate::EbnfSerializer;
 
 impl EbnfNode {
     pub fn from_precedence_parser(

crates/codegen/grammar/src/grammar.rs

@@ -2,10 +2,9 @@ use std::collections::{BTreeSet, HashMap};
 
 use semver::Version;
 
-use super::{
-    GrammarVisitor, ParserDefinitionRef, PrecedenceParserDefinitionRef, ScannerDefinitionRef,
-    TriviaParserDefinitionRef, Visitable,
-};
+use crate::parser_definition::{ParserDefinitionRef, TriviaParserDefinitionRef};
+use crate::visitor::{GrammarVisitor, Visitable};
+use crate::{PrecedenceParserDefinitionRef, ScannerDefinitionRef};
 
 pub struct Grammar {
     pub name: String,

crates/codegen/grammar/src/parser_definition.rs

@@ -1,10 +1,8 @@
 use std::fmt::Debug;
 use std::rc::Rc;
 
-use super::{
-    GrammarVisitor, PrecedenceParserDefinitionRef, ScannerDefinitionRef, VersionQualityRange,
-    Visitable,
-};
+use crate::visitor::{GrammarVisitor, Visitable};
+use crate::{PrecedenceParserDefinitionRef, ScannerDefinitionRef, VersionQualityRange};
 
 pub trait ParserDefinition: Debug {
     fn name(&self) -> &'static str;

crates/codegen/grammar/src/precedence_parser_definition.rs

@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 use std::rc::Rc;
 
-use super::{GrammarVisitor, ParserDefinitionNode, Visitable};
+use crate::{GrammarVisitor, ParserDefinitionNode, Visitable};
 
 pub trait PrecedenceParserDefinition: Debug {
     fn name(&self) -> &'static str;

crates/codegen/grammar/src/scanner_definition.rs

@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 use std::rc::Rc;
 
-use super::{GrammarVisitor, VersionQualityRange, Visitable};
+use crate::{GrammarVisitor, VersionQualityRange, Visitable};
 
 pub trait ScannerDefinition: Debug {
     fn name(&self) -> &'static str;

crates/codegen/grammar/src/visitor.rs

@@ -1,4 +1,4 @@
-use super::{
+use crate::{
     Grammar, ParserDefinitionNode, ParserDefinitionRef, PrecedenceParserDefinitionNode,
     PrecedenceParserDefinitionRef, ScannerDefinitionNode, ScannerDefinitionRef,
     TriviaParserDefinitionRef,

crates/codegen/language/definition/src/compiler/analysis/definitions.rs

@@ -1,13 +1,9 @@
 use std::collections::HashSet;
 
-use crate::{
-    compiler::{
-        analysis::{Analysis, ItemMetadata},
-        version_set::VersionSet,
-    },
-    internals::Spanned,
-    model::{Identifier, SpannedItem, SpannedVersionSpecifier},
-};
+use crate::compiler::analysis::{Analysis, ItemMetadata};
+use crate::compiler::version_set::VersionSet;
+use crate::internals::Spanned;
+use crate::model::{Identifier, SpannedItem, SpannedVersionSpecifier};
 
 pub(crate) fn analyze_definitions(analysis: &mut Analysis) {
     collect_top_level_items(analysis);

crates/codegen/language/definition/src/compiler/analysis/mod.rs

@@ -8,15 +8,12 @@ use std::rc::Rc;
 use indexmap::IndexMap;
 use proc_macro2::Span;
 
-use crate::{
-    compiler::analysis::{
-        definitions::analyze_definitions, reachability::analyze_reachability,
-        references::analyze_references,
-    },
-    compiler::version_set::VersionSet,
-    internals::{ErrorsCollection, ParseOutput, Spanned},
-    model::{Identifier, SpannedItem, SpannedLanguage},
-};
+use crate::compiler::analysis::definitions::analyze_definitions;
+use crate::compiler::analysis::reachability::analyze_reachability;
+use crate::compiler::analysis::references::analyze_references;
+use crate::compiler::version_set::VersionSet;
+use crate::internals::{ErrorsCollection, ParseOutput, Spanned};
+use crate::model::{Identifier, SpannedItem, SpannedLanguage};
 
 pub(crate) struct Analysis {
     pub errors: ErrorsCollection,