Rename 'Grammar' optional step group to 'Antlr' in deploy_to_develop pipeline

Fixes #2057

The  decorator was used for three pipeline steps that
handle ANTLR-specific grammar files (.g/.g4). The name "Grammar" is too generic
and ambiguous — it does not make clear which grammar tool or technology is involved.

Rename the optional step group from "Grammar" to "Antlr" to:
- Align with all other optional step groups in the pipeline that are named after
  their specific technology (Java, Scala, Kotlin, Groovy, AspectJ, Clojure, etc.)
- Make the user-facing CLI --groups flag, REST API, and UI unambiguous
- Clearly communicate that these steps are exclusively for ANTLR grammar files

The three affected steps are:
- find_grammar_packages: finds java packages in .g/.g4 source files
- map_grammar_to_class: maps .class files to their .g/.g4 source
- map_jar_to_grammar_source: maps .jar files to their ANTLR source directory

Note: Internal class names (GrammarLanguage, grammar_package, grammar_to_class)
are database-persisted identifiers and are intentionally NOT changed to avoid
requiring a data migration.

Backward compatibility note: Existing pipeline configs or API calls using
"--groups Grammar" must be updated to "--groups Antlr" after this change.

Author: Gyan Ranjan Panda

scanpipe/pipelines/deploy_to_develop.py

@@ -250,21 +250,21 @@ def map_jar_to_kotlin_source(self):
             project=self.project, jvm_lang=jvm.KotlinLanguage, logger=self.log
         )
 
-    @optional_step("Grammar")
+    @optional_step("Antlr")
     def find_grammar_packages(self):
         """Find the java package of the .g/.g4 source files."""
         d2d.find_jvm_packages(
             project=self.project, jvm_lang=jvm.GrammarLanguage, logger=self.log
         )
 
-    @optional_step("Grammar")
+    @optional_step("Antlr")
     def map_grammar_to_class(self):
         """Map a .class compiled file to its .g/.g4 source."""
         d2d.map_jvm_to_class(
             project=self.project, jvm_lang=jvm.GrammarLanguage, logger=self.log
         )
 
-    @optional_step("Grammar")
+    @optional_step("Antlr")
     def map_jar_to_grammar_source(self):
         """Map .jar files to their related source directory."""
         d2d.map_jar_to_jvm_source(