Fix emphasis vs definitions in cake eating lectures

Changes per #721:
- exogenous (cake_eating_egm.md)
- adapted (cake_eating_stochastic.md)
- state (cake_eating_stochastic.md)
- control (cake_eating_stochastic.md)
- topologically conjugate (cake_eating_time_iter.md)

All terms changed from italic to bold as they are definitions per style guide.

Author: mmcky

lectures/cake_eating_egm.md

@@ -114,7 +114,7 @@ Let $(u')^{-1}$ be the inverse function of $u'$.
 
 The idea is this:
 
-* First, we fix an *exogenous* grid $\{k_i\}$ for capital ($k = x - c$).
+* First, we fix an **exogenous** grid $\{k_i\}$ for capital ($k = x - c$).
 * Then we obtain  $c_i$ via
 
 ```{math}

lectures/cake_eating_stochastic.md

@@ -164,13 +164,13 @@ In summary, the agent's aim is to select a path $c_0, c_1, c_2, \ldots$ for cons
 1. nonnegative,
 1. feasible in the sense of {eq}`outcsdp0`,
 1. optimal, in the sense that it maximizes {eq}`texs0_og2` relative to all other feasible consumption sequences, and
-1. *adapted*, in the sense that the action $c_t$ depends only on
+1. **adapted**, in the sense that the action $c_t$ depends only on
    observable outcomes, not on future outcomes such as $\xi_{t+1}$.
 
 In the present context
 
-* $x_t$ is called the *state* variable --- it summarizes the "state of the world" at the start of each period.
-* $c_t$ is called the *control* variable --- a value chosen by the agent each period after observing the state.
+* $x_t$ is called the **state** variable --- it summarizes the "state of the world" at the start of each period.
+* $c_t$ is called the **control** variable --- a value chosen by the agent each period after observing the state.
 
 ### The Policy Function Approach
 

lectures/cake_eating_time_iter.md

@@ -237,7 +237,7 @@ whenever $\sigma \in \mathscr P$.
 It is possible to prove that there is a tight relationship between iterates of
 $K$ and iterates of the Bellman operator.
 
-Mathematically, the two operators are *topologically conjugate*.
+Mathematically, the two operators are **topologically conjugate**.
 
 Loosely speaking, this means that if iterates of one operator converge then
 so do iterates of the other, and vice versa.