fix typo tokenizer -> tokenizerSource (#89)

## Description
Typo in docs

### Type of change
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [x] Documentation update (improves or adds clarity to existing
documentation)

### Tested on
- [ ] iOS
- [ ] Android

### Testing instructions
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Include setup details if necessary. -->

### Screenshots
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### Related issues
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### Checklist
- [ ] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have updated the documentation accordingly
- [ ] My changes generate no new warnings

### Additional notes
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Co-authored-by: Mateusz Kopciński <[email protected]>

Author: mkopcins

docs/docs/fundamentals/loading-models.md

@@ -40,6 +40,6 @@ import { useLLM } from 'react-native-executorch';
 
 const llama = useLLM({
   modelSource: 'https://.../llama3_2.pte',
-  tokenizer: require('../assets/tokenizer.bin'),
+  tokenizerSource: require('../assets/tokenizer.bin'),
 });
 ```

docs/docs/llms/running-llms.md

@@ -18,7 +18,7 @@ import { useLLM, LLAMA3_2_1B } from 'react-native-executorch';
 
 const llama = useLLM({
   modelSource: LLAMA3_2_1B,
-  tokenizer: require('../assets/tokenizer.bin'),
+  tokenizerSource: require('../assets/tokenizer.bin'),
   contextWindowLength: 3,
 });
 ```
@@ -37,7 +37,7 @@ Given computational constraints, our architecture is designed to support only on
 
 **`modelSource`** - A string that specifies the location of the model binary. For more information, take a look at [loading models](../fundamentals/loading-models.md) section.
 
-**`tokenizer`** - URL to the binary file which contains the tokenizer
+**`tokenizerSource`** - URL to the binary file which contains the tokenizer
 
 **`contextWindowLength`** - The number of messages from the current conversation that the model will use to generate a response. The higher the number, the more context the model will have. Keep in mind that using larger context windows will result in longer inference time and higher memory usage.
 
@@ -62,7 +62,7 @@ In order to send a message to the model, one can use the following code:
 ```typescript
 const llama = useLLM(
     modelSource: LLAMA3_2_1B,
-    tokenizer: require('../assets/tokenizer.bin'),
+    tokenizerSource: require('../assets/tokenizer.bin'),
 );
 
 ...