Minor syntax cleanup.

examples/cytology/Cytology.thy

@@ -69,7 +69,7 @@ onto_class procaryotic_cells = cell +
 onto_class eucaryotic_cells = cell + 
     organelles :: "organelles' list"
     invariant has_nucleus :: "\<lambda>\<sigma>::eucaryotic_cells. \<exists> org \<in> set (organelles \<sigma>). is\<^sub>n\<^sub>u\<^sub>c\<^sub>l\<^sub>e\<^sub>u\<^sub>s org"
-    \<comment>\<open>Cells must have at least one nucleus. However, this should be executable.\<close>
+    \<comment> \<open>Cells must have at least one nucleus. However, this should be executable.\<close>
 
 find_theorems (70)name:"eucaryotic_cells"
 find_theorems name:has_nucleus

src/ontologies/Conceptual/Conceptual.thy

@@ -136,7 +136,7 @@ text\<open>Now, we can use these definitions in order to generate code for these
 Note, however, that not everything that we can write in an invariant (basically: HOL) is executable,
 or even compilable by the code generator setup:\<close>
 
-ML\<open> val cr_inv_code = @{code "cr_inv"} \<close> \<comment>\<open>works albeit thm is abstract ...\<close>
+ML\<open> val cr_inv_code = @{code "cr_inv"} \<close> \<comment> \<open>works albeit thm is abstract ...\<close>
 text\<open>while in :\<close>
 (* ML\<open> val br_inv_code = @{code "br_inv"} \<close> \<comment>\<open>this does not work ...\<close> *)
 
@@ -144,7 +144,7 @@ text\<open>... the compilation fails due to the fact that nothing prevents the u
      to define an infinite relation between \<^typ>\<open>A\<close> and  \<^typ>\<open>C\<close>. However, the alternative
 variant: \<close>
 
-ML\<open> val br'_inv_code = @{code "br'_inv"} \<close> \<comment>\<open>does work ...\<close>
+ML\<open> val br'_inv_code = @{code "br'_inv"} \<close> \<comment> \<open>does work ...\<close>
 
 text\<open>... is compilable ...\<close>