Initial support for .csproj, .slnx, .proj, .props and .targets files (#64)

This PR implements syntax highlighting for following XML-based file
types:
- `.csproj`
- `.slnx`
- `.proj`
- `.props`
- `.targets`

The syntax highlighting is done by replicating the standard XML grammar
(from Zed XML extension) for each of the file types.

Additionally, this PR includes support for running .NET Restore/Build
for currently-opened Solution or Project file, through Zed Tasks.

---

**EDIT:** 
- The PR now includes `.proj` extension too. 
- The `.proj`, `.props` and `.targets` combined into a single language
called "MSBuild".
- Since the grammars share the same queries (sourced from Original Zed
XML extension), the PR has been updated to use symlinks to reduce
duplication.

---------

Co-authored-by: MrSubidubi <dev@bahn.sh>

Author: Sathiyaraman-M

extension.toml

@@ -24,3 +24,8 @@ language = "CSharp"
 [grammars.c_sharp]
 repository = "https://github.com/tree-sitter/tree-sitter-c-sharp"
 commit = "485f0bae0274ac9114797fc10db6f7034e4086e3"
+
+[grammars.xml]
+repository = "https://github.com/tree-sitter-grammars/tree-sitter-xml"
+commit = "863dbc381f44f6c136a399e684383b977bb2beaa"
+path = "xml"

languages/csproj/config.toml

@@ -0,0 +1,9 @@
+name = "C# Project File"
+grammar = "xml"
+path_suffixes = ["csproj"]
+block_comment = ["<!-- ", " -->"]
+autoclose_before = "<"
+brackets = [{ start = "<", end = ">", close = true, newline = true }]
+prettier_parser_name = "xml"
+prettier_plugins = ["@prettier/plugin-xml"]
+hard_tabs = true

languages/csproj/highlights.scm

@@ -0,0 +1 @@
+../msbuild/highlights.scm

languages/csproj/indents.scm

@@ -0,0 +1 @@
+../msbuild/indents.scm

languages/csproj/outline.scm

@@ -0,0 +1 @@
+../msbuild/outline.scm

languages/csproj/tasks.json

@@ -0,0 +1,24 @@
+[
+  {
+    "label": "Restore Current Project",
+    "command": "dotnet restore",
+    "args": ["$ZED_FILE"],
+    "use_new_terminal": false,
+    "allow_concurrent_runs": false,
+    "reveal": "always",
+    "reveal_target": "center",
+    "hide": "on_success",
+    "shell": "system"
+  },
+  {
+    "label": "Build Current Project",
+    "command": "dotnet build",
+    "args": ["$ZED_FILE"],
+    "use_new_terminal": false,
+    "allow_concurrent_runs": false,
+    "reveal": "always",
+    "reveal_target": "center",
+    "hide": "on_success",
+    "shell": "system"
+  }
+]

languages/msbuild/config.toml

@@ -0,0 +1,9 @@
+name = "MSBuild File"
+grammar = "xml"
+path_suffixes = ["proj", "props", "targets"]
+block_comment = ["<!-- ", " -->"]
+autoclose_before = "<"
+brackets = [{ start = "<", end = ">", close = true, newline = true }]
+prettier_parser_name = "xml"
+prettier_plugins = ["@prettier/plugin-xml"]
+hard_tabs = true

languages/msbuild/highlights.scm

@@ -0,0 +1,206 @@
+; XML declaration
+"xml" @keyword
+
+[
+  "version"
+  "encoding"
+  "standalone"
+] @property
+
+(EncName) @string.special
+
+(VersionNum) @number
+
+[
+  "yes"
+  "no"
+] @boolean
+
+; Processing instructions
+(PI) @embedded
+
+(PI
+  (PITarget) @keyword)
+
+; Element declaration
+(elementdecl
+  "ELEMENT" @keyword
+  (Name) @tag)
+
+(contentspec
+  (_
+    (Name) @property))
+
+"#PCDATA" @type.builtin
+
+[
+  "EMPTY"
+  "ANY"
+] @string.special.symbol
+
+[
+  "*"
+  "?"
+  "+"
+] @operator
+
+; Entity declaration
+(GEDecl
+  "ENTITY" @keyword
+  (Name) @constant)
+
+(GEDecl
+  (EntityValue) @string)
+
+(NDataDecl
+  "NDATA" @keyword
+  (Name) @label)
+
+; Parsed entity declaration
+(PEDecl
+  "ENTITY" @keyword
+  "%" @operator
+  (Name) @constant)
+
+(PEDecl
+  (EntityValue) @string)
+
+; Notation declaration
+(NotationDecl
+  "NOTATION" @keyword
+  (Name) @constant)
+
+(NotationDecl
+  (ExternalID
+    (SystemLiteral
+      (URI) @string.special)))
+
+; Attlist declaration
+(AttlistDecl
+  "ATTLIST" @keyword
+  (Name) @tag)
+
+(AttDef
+  (Name) @property)
+
+(AttDef
+  (Enumeration
+    (Nmtoken) @string))
+
+(DefaultDecl
+  (AttValue) @string)
+
+[
+  (StringType)
+  (TokenizedType)
+] @type.builtin
+
+(NotationType
+  "NOTATION" @type.builtin)
+
+[
+  "#REQUIRED"
+  "#IMPLIED"
+  "#FIXED"
+] @attribute
+
+; Entities
+(EntityRef) @constant
+
+((EntityRef) @constant.builtin
+  (#any-of? @constant.builtin "&" "<" ">" """ "'"))
+
+(CharRef) @constant
+
+(PEReference) @constant
+
+; External references
+[
+  "PUBLIC"
+  "SYSTEM"
+] @keyword
+
+(PubidLiteral) @string.special
+
+(SystemLiteral
+  (URI) @markup.link)
+
+; Processing instructions
+(XmlModelPI
+  "xml-model" @keyword)
+
+(StyleSheetPI
+  "xml-stylesheet" @keyword)
+
+(PseudoAtt
+  (Name) @property)
+
+(PseudoAtt
+  (PseudoAttValue) @string)
+
+; Doctype declaration
+(doctypedecl
+  "DOCTYPE" @keyword)
+
+(doctypedecl
+  (Name) @type)
+
+; Tags
+(STag
+  (Name) @tag)
+
+(ETag
+  (Name) @tag)
+
+(EmptyElemTag
+  (Name) @tag)
+
+; Attributes
+(Attribute
+  (Name) @property)
+
+(Attribute
+  (AttValue) @string)
+
+; Delimiters & punctuation
+[
+  "<?"
+  "?>"
+  "<!"
+  "]]>"
+  "<"
+  ">"
+  "</"
+  "/>"
+] @punctuation.delimiter
+
+[
+  "("
+  ")"
+  "["
+  "]"
+] @punctuation.bracket
+
+[
+  "\""
+  "'"
+] @punctuation.delimiter
+
+[
+  ","
+  "|"
+  "="
+] @operator
+
+; Text
+(CharData) @markup
+
+(CDSect
+  (CDStart) @markup.heading
+  (CData) @markup.raw
+  "]]>" @markup.heading)
+
+; Misc
+(Comment) @comment
+
+(ERROR) @error

languages/msbuild/indents.scm

@@ -0,0 +1,5 @@
+(STag
+  ">" @end) @indent
+
+(EmptyElemTag
+  "/>" @end) @indent

languages/msbuild/outline.scm

@@ -0,0 +1,9 @@
+(element
+  (STag
+    (Name) @name)) @item
+
+(EmptyElemTag
+  (Name) @name) @item
+
+(doctypedecl
+  (Name) @name) @item