docs: quote pip extras install examples (#395)

* docs: quote pip extras install examples

* docs: quote research extra in analyzer messages

---------

Co-authored-by: nyxst4ck <289980115+nyxst4ck@users.noreply.github.com>

README.md

@@ -135,7 +135,7 @@ provides features designed to support research into the semantics of model inter
 optional `research` extra:
 
 ```sh
-pip install -U heretic-llm[research]
+pip install -U 'heretic-llm[research]'
 ```
 
 This gives you access to the following functionality:

src/heretic/analyzer.py

@@ -42,7 +42,7 @@ class Analyzer:
                 (
                     "[red]Research dependencies not found. Printing residual geometry requires "
                     "installing Heretic with the optional research feature, i.e., "
-                    'using "pip install -U heretic-llm\\[research]".[/]'
+                    "using \"pip install -U 'heretic-llm\\[research]'\".[/]"
                 )
             )
             return
@@ -168,7 +168,7 @@ class Analyzer:
                 (
                     "[red]Research dependencies not found. Plotting residuals requires "
                     "installing Heretic with the optional research feature, i.e., "
-                    'using "pip install -U heretic-llm\\[research]".[/]'
+                    "using \"pip install -U 'heretic-llm\\[research]'\".[/]"
                 )
             )
             return