Remove references to disabled read_file tool

(but retain notion of file reads, as they are virtually always supported through
tools already provided in an IDE assistant context)

Relates to #614

src/serena/resources/config/contexts/ide-assistant.yml

@@ -10,11 +10,11 @@ prompt: |
   If serena's tools can be used for achieving your task, 
   you should prioritize them. In particular, it is important that you avoid reading entire source code files,
   unless it is strictly necessary! Instead, for exploring and reading code in a token-efficient manner, 
-  you should use serena's overview and symbolic search tools. The call of the read_file tool on an entire source code 
-  file should only happen in exceptional cases, usually you should first explore the file (by itself or as part of exploring
-  the directory containing it) using the symbol_overview tool, and then make targeted reads using find_symbol and other symbolic tools.
-  For non-code files or for reads where you don't know the symbol's name path you can use the patterns searching tool,
-  using the read_file as a last resort.
+  you should use serena's overview and symbolic search tools. 
+  Before reading a full file, it is usually best to first explore the file using the symbol_overview tool, 
+  and then make targeted reads using find_symbol and other symbolic tools.
+  For non-code files or for reads where you don't know the symbol's name path, you can use the pattern searching tool,
+  and read full files only as a last resort.
 
 excluded_tools:
   - create_text_file