Add completion_query_characters in language (#27175)

Closes #18581

Now characters for completing query and word characters, which are
responsible for selecting words by double clicking or navigating, are
different. This fixes a bunch of things:

For settings.json, this improves completions to treat the whole string
as a completion query, instead of just the last word. We now added
"space" as a completion query character without it being a word
character.

For keymap.json, this improves selecting part of an action as the ":"
character is only a completion character and not a word character. So,
completions would still trigger on ":" and query capture will treat ":"
as a word, but for actions like selections and navigation, ":" will be
treated as punctuation.

Before:
Unnecessary related suggestions as query is only the last word which is
"d".
<img width="300" alt="image"
src="https://github.com/user-attachments/assets/8199a715-7521-49dd-948b-e6aaed04c488"
/>

Double clicking `ToggleFold` selects the whole action:
<img width="300" alt="image"
src="https://github.com/user-attachments/assets/c7f91a6b-06d5-45b6-9d59-61a1b2deda71"
/>

After:
Now query is "one d" and it shows only matched ones.
<img width="300" alt="image"
src="https://github.com/user-attachments/assets/1455dfbc-9906-42e8-b8aa-b3f551194ca2"
/>

Double clicking `ToggleFold` only selects part of the action, which is
more refined behavior.
<img width="300" alt="image"
src="https://github.com/user-attachments/assets/34b1c3c2-184f-402f-9dc8-73030a8c370f"
/>

Release Notes:

- Improved autocomplete suggestions in `settings.json`, now whole string
is queried instead of just last word of string, which filters out lot of
false positives.
- Improved selection of action in `keymap.json`, where now you can
double click to only select certain part of action, instead of selecting
whole action.

---------

Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-authored-by: Ben Kunkle <ben@zed.dev>

crates/language/src/buffer.rs

@@ -4727,23 +4727,27 @@ impl CharClassifier {
     }
 
     pub fn kind_with(&self, c: char, ignore_punctuation: bool) -> CharKind {
-        if c.is_whitespace() {
-            return CharKind::Whitespace;
-        } else if c.is_alphanumeric() || c == '_' {
+        if c.is_alphanumeric() || c == '_' {
             return CharKind::Word;
         }
 
         if let Some(scope) = &self.scope {
-            if let Some(characters) = scope.word_characters() {
+            let characters = if self.for_completion {
+                scope.completion_query_characters()
+            } else {
+                scope.word_characters()
+            };
+            if let Some(characters) = characters {
                 if characters.contains(&c) {
-                    if c == '-' && !self.for_completion && !ignore_punctuation {
-                        return CharKind::Punctuation;
-                    }
                     return CharKind::Word;
                 }
             }
         }
 
+        if c.is_whitespace() {
+            return CharKind::Whitespace;
+        }
+
         if ignore_punctuation {
             CharKind::Word
         } else {

crates/language/src/language.rs

@@ -700,6 +700,9 @@ pub struct LanguageConfig {
     /// If configured, this language contains JSX style tags, and should support auto-closing of those tags.
     #[serde(default)]
     pub jsx_tag_auto_close: Option<JsxTagAutoCloseConfig>,
+    /// A list of characters that Zed should treat as word characters for completion queries.
+    #[serde(default)]
+    pub completion_query_characters: HashSet<char>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, Default, JsonSchema)]
@@ -765,6 +768,8 @@ pub struct LanguageConfigOverride {
     #[serde(default)]
     pub word_characters: Override<HashSet<char>>,
     #[serde(default)]
+    pub completion_query_characters: Override<HashSet<char>>,
+    #[serde(default)]
     pub opt_into_language_servers: Vec<LanguageServerName>,
 }
 
@@ -816,6 +821,7 @@ impl Default for LanguageConfig {
             prettier_parser_name: None,
             hidden: false,
             jsx_tag_auto_close: None,
+            completion_query_characters: Default::default(),
         }
     }
 }
@@ -1705,6 +1711,16 @@ impl LanguageScope {
         )
     }
 
+    /// Returns a list of language-specific characters that are considered part of
+    /// a completion query.
+    pub fn completion_query_characters(&self) -> Option<&HashSet<char>> {
+        Override::as_option(
+            self.config_override()
+                .map(|o| &o.completion_query_characters),
+            Some(&self.language.config.completion_query_characters),
+        )
+    }
+
     /// Returns a list of bracket pairs for a given language with an additional
     /// piece of information about whether the particular bracket pair is currently active for a given language.
     pub fn brackets(&self) -> impl Iterator<Item = (&BracketPair, bool)> {