Add titles to concept pages

Author: dlesbre

docs/concepts/modular_analysis.md

@@ -4,7 +4,9 @@ title: Modular analysis
 parent: Concepts
 ---
 
-A modular analysis can analyze *parts* of a program, for instance,
+# Modular analysis
+
+A **modular analysis** can analyze *parts* of a program, for instance,
 analyze a function `f` without having access to the code of the
 functions that call `f` or are called by `f`.
 

docs/concepts/whole_program_analysis.md

@@ -4,11 +4,13 @@ title: Whole-program analysis
 parent: Concepts
 ---
 
-A whole-program analysis requires the analyzer to know the entire
+## Whole program analysis
+
+A **whole-program analysis** requires the analyzer to know the entire
 program to start. It thus cannot[^1] be applied to parts of a program like
 a library or a single function, unlike a [modular
 analysis](/docs/concepts/modular_analysis.html).
 
 Codex allows performing both modular and whole-program analyses.
 
-[^1]: Note that it is often possible to work around the problem by inserting stubs, but these remains work-arounds.
+[^1]: Note that it is often possible to work around the problem by inserting stubs, but these remains workarounds.